Handle overflowing route-hint fee aggregates - #4716

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TheBlueMatt merged 1 commit into
lightningdevkit:mainfrom
tnull:tnull/2026-05-fix-route-hint-overflow
Jun 18, 2026
Merged

Handle overflowing route-hint fee aggregates#4716
TheBlueMatt merged 1 commit into
lightningdevkit:mainfrom
tnull:tnull/2026-05-fix-route-hint-overflow

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Crafted route hints can overflow aggregate downstream proportional fees when the payer disables the routing fee cap. Treat such paths as unusable so route finding fails cleanly instead of panicking.

Reported by Project Loupe

Crafted route hints can overflow aggregate downstream proportional fees
when the payer disables the routing fee cap. Treat such paths as
unusable so route finding fails cleanly instead of panicking.
Co-Authored-By: HAL 9000
Signed-off-by: Elias Rohrer <dev@tnull.de>
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I've assigned @wpaulino as a reviewer!
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No issues found.

I reviewed the entire diff and traced the supporting code paths:

  • max_final_value_msat now returns Result<(usize, u64), usize>, returning idx + 1 on aggregate-fee overflow. This index is always in bounds, since overflow can only occur when at least one downstream hop exists (compute_aggregated_base_prop_fee returns Ok((0,0)) for an empty iterator), so idx + 1 <= hops.len() - 1.
  • The get_route handler indexes payment_path.hops[candidate_idx_to_skip] safely, logs, marks the candidate exhausted, and continue 'paths_collection. used_liquidities persists across loop iterations, and add_entry saturating-subtracts the u64::MAX value to 0, excluding the candidate — so progress is guaranteed and no infinite loop occurs.
  • mark_candidate_liquidity_exhausted writes both (scid, false)/(scid, true) for clear hops and candidate.id() for the no-scid case, which is consistent with the keys read in max_final_value_msat (hop.candidate.id()) and add_entry ($candidate.id()).
  • The test correctly disables the fee cap (max_total_routing_fee_msat: None) and uses two route-hint hops with proportional_millionths: u32::MAX to trigger the overflow, asserting route.is_err().

Minor (non-blocking) cross-cutting note: the new mark_candidate_liquidity_exhausted helper overlaps with the inline scid-marking block at router.rs:3697-3700 (victim_candidate). Per the repo's DRY guidance that block could call the helper, though doing so would also add the no-scid/blinded else branch, which is a slight behavior change — so leaving it as-is is defensible.

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thanks

match payment_path.max_final_value_msat(&used_liquidities, channel_saturation_pow_half) {
Ok(contribution) => contribution,
Err(candidate_idx_to_skip) => {
let candidate = &payment_path.hops[candidate_idx_to_skip].0.candidate;

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The fact that this can't index OOB is incredibly subtle (compute_aggregated_base_prop_fee won't fail if next_hops_feerates_iter is empty, which will happen if we're at the end). Might be worth clarifying somewhere in a comment.

@TheBlueMatt
TheBlueMatt merged commit 61e3cab into lightningdevkit:mainJun 18, 2026
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This was referenced Jun 18, 2026
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Backported to 0.2 in #4722.

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Backported to 0.1 in #4720.

TheBlueMatt added a commit that referenced this pull request Jun 19, 2026
v0.1.10 - Jun 18, 2026 - "Loupe de Loupe"
API Updates
===========
* `DefaultMessageRouter` will now always generate blinded message paths that
provide no privacy (where our node is the introduction node) for nodes with
public channels. This works around an issue which will appear for any nodes
with LND peers that enable onion messaging - such peers will refuse to
forward BOLT 12 messages from unknown third parties, which most BOLT 12
payers rely on today (#4647).
* Explicit `amount_msats` of 0 is rejected in BOLT 12 `Offer`s; `OfferBuilder`
now maps 0-amounts to an amount of `None` (#4324).
Bug Fixes
=========
* Async `ChannelMonitorUpdate` persistence operations which complete, but are
not marked as complete in a persisted `ChannelManager` prior to restart,
followed immediately by a block connection and then another restart could
result in some channel operations hanging leading for force-closures (#4377).
* If an MPP payment is claimed but `ChannelMonitorUpdate`s for some parts are
still being completed asynchronously, further channel updates (e.g.
forwarding another payment) are pending and the node restarts, the channel
could have become stuck (#4520).
* The presence of unconfirmed transactions actually no longer causes
`ElectrumSyncClient` to spuriously fail to sync (#4590).
* `FilesystemStore::list_all_keys` will no longer fail if there are stale
intermediate files lying around from a previous unclean shutdown (#4618).
* When forwarding an HTLC while in a blinded path with proportional fees over
200%, LDK will no longer spuriously allow a forward that pays us 1 msat too
little in fees (#4697).
* Fixed a rare case where a channel could get stuck on reconnect when using
both async `ChannelMonitorUpdate` persistence and async signing (#4684).
* `Event::PaymentSent::fee_paid_msat` is no longer `None` in cases where
`ChannelManager::abandon_payment` was called before the payment ultimately
completes anyway (#4651).
* Syncing a `ChainMonitor` using the `Confirm` trait will no longer write some
full `ChannelMonitor`s to disk several times per block (#4544).
* `OMDomainResolver` now correctly accounts for failed queries when rate
limiting, ensuring we continue to respond to queries after failures (#4591).
* Calling `ChannelManager::send_payment_with_route` without a `route_params`
and with an invalid `Route` will no longer panic (#4707).
* `lightning-custom-message`'s handling of `peer_connected` events now ensures
that sub-handlers will see a `peer_disconnected` event if a different
sub-handler refused the connection by `Err`ing `peer_connected` (#4595).
* Incomplete MPP keysend payments will no longer see their HTLCs held until
expiry (#4558).
* `InvoiceRequestBuilder` will no longer accept a `quantity` of `0` for a
BOLT 12 `Offer`, allowing any quantity up to a bound (#4667).
* `lightning-custom-message` handlers that return `Ok(None)` when asked to
deserialize a message in their defined range no longer cause panics (#4709).
* Several spurious debug assertions were fixed (#4537, #4618).
Security
========
0.1.10 fixes a sanitization issue and several denial-of-service vulnerabilities.
* `Bolt11Invoice::recover_payee_pub_key` no longer panics if called on an
invoice which set an explicit public key, rather than relying on public key
recovery. This method is called from `payment_parameters_from_invoice` and
`payment_parameters_from_variable_amount_invoice` (#4717).
* Maliciously-crafted unpayable invoices which have overflowing feerates will
no longer cause an `unwrap` failure panic (#4716).
* `possiblyrandom` did not properly generate random data except when it was
explicitly configured to. By default this means LDK is vulnerable to various
HashDoS attacks (#4719).
* `OMNameResolver` will no longer panic when looking up payment instructions
which include unicode characters at the start of a TXT record (#4718).
* `PrintableString` did not properly sanitize unicode format characters,
allowing an attacker to corrupt the rendering of logs or UI (#4593, #4605).
* RGS data is now limited in how large of a graph it is able to cause a client
to store in memory. Note that RGS data is still considered a DoS vector in
general and you should only use semi-trusted RGS data (#4713).
* Counterparty-provided strings in failure messages are no longer logged in
full, reducing the ability of such a counterparty to spam our logs (#4714).
* Reading a corrupted `ChannelManager` or `ProbabilisticScorer` can no longer
cause us to allocate large amounts of memory (#4712).
Thanks to Project Loupe for reporting most of the issues fixed in this release.
TheBlueMatt added a commit to TheBlueMatt/rust-lightning that referenced this pull request Jun 23, 2026
v0.2.3 - Jun 18, 2026 - "Through the Loupe"
API Updates
===========
* `DefaultMessageRouter` will now always generate blinded message paths that
provide no privacy (where our node is the introduction node) for nodes with
public channels. This works around an issue which will appear for any nodes
with LND peers that enable onion messaging - such peers will refuse to
forward BOLT 12 messages from unknown third parties, which most BOLT 12
payers rely on today (lightningdevkit#4647).
* Explicit `amount_msats` of 0 is rejected in BOLT 12 `Offer`s; `OfferBuilder`
now maps 0-amounts to an amount of `None` (lightningdevkit#4324).
Bug Fixes
=========
* `Features::supports_zero_conf` no longer clears the `ZeroConf` features and
`Features::requires_zero_conf` now correctly reports required, rather than
supported, status (lightningdevkit#4517).
* If an MPP payment is claimed but `ChannelMonitorUpdate`s for some parts are
still being completed asynchronously, further channel updates (e.g.
forwarding another payment) are pending and the node restarts, the channel
could have become stuck (lightningdevkit#4520).
* The presence of unconfirmed transactions actually no longer causes
`ElectrumSyncClient` to spuriously fail to sync (lightningdevkit#4590).
* LSPS1, LSPS2, and LSPS5 persistence will no longer get stuck and refuse to
persist again after a single failure from the KVStore (lightningdevkit#4597, lightningdevkit#4282).
* Dropping the future returned by
`OutputSweeper::regenerate_and_broadcast_spend_if_necessary` no longer
results in future calls to the same method being spuriously ignored (lightningdevkit#4598).
* Used async-receive offers are no longer refreshed on every timer tick once
their refresh time is reached (lightningdevkit#4672).
* `FilesystemStore::list_all_keys` will no longer fail if there are stale
intermediate files lying around from a previous unclean shutdown (lightningdevkit#4618).
* When forwarding an HTLC while in a blinded path with proportional fees over
200%, LDK will no longer spuriously allow a forward that pays us 1 msat too
little in fees (lightningdevkit#4697).
* Fixed a rare case where a channel could get stuck on reconnect when using
both async `ChannelMonitorUpdate` persistence and async signing (lightningdevkit#4684).
* If we had exactly zero balance in a zero-fee-commitment channel, the
counterparty was able to splice all of their balance out, violating the
reserve requirements they'd otherwise be forced to keep (lightningdevkit#4580).
* Providing an `Event::HTLCIntercepted` to the `LSPS2ServiceHandler` twice no
longer results in spuriously opening a channel early (lightningdevkit#4656).
* `Event::PaymentSent::fee_paid_msat` is no longer `None` in cases where
`ChannelManager::abandon_payment` was called before the payment ultimately
completes anyway (lightningdevkit#4651).
* `AnchorDescriptor::previous_utxo` now provides the correct `script_pubkey`
for non-zero-commitment-fee anchor channels (lightningdevkit#4669).
* Syncing a `ChainMonitor` using the `Confirm` trait will no longer write some
full `ChannelMonitor`s to disk several times per block (lightningdevkit#4544).
* `OMDomainResolver` now correctly accounts for failed queries when rate
limiting, ensuring we continue to respond to queries after failures (lightningdevkit#4591).
* Calling `ChannelManager::send_payment_with_route` without a `route_params`
and with an invalid `Route` will no longer panic (lightningdevkit#4707).
* `LSPS2ServiceHandler::channel_open_failed` now correctly fails intercepted
HTLCs rather than allowing them to fail just before expiry (lightningdevkit#4677).
* `StaticInvoice::is_offer_expired` was corrected to check offer, rather than
static invoice, expiry (lightningdevkit#4594).
* `lightning-custom-message`'s handling of `peer_connected` events now ensures
that sub-handlers will see a `peer_disconnected` event if a different
sub-handler refused the connection by `Err`ing `peer_connected` (lightningdevkit#4595).
* Replay protection for LSPS5 signatures now detects replays which are only
different in the encoded signature's case (lightningdevkit#4701).
* When `lightning-liquidity` is configured in the background processor, there
is no longer a stream of `Persisting LiquidityManager...` log spam (lightningdevkit#4246).
* Incomplete MPP keysend payments will no longer see their HTLCs held until
expiry (lightningdevkit#4558).
* `InvoiceRequestBuilder` will no longer accept a `quantity` of `0` for a
BOLT 12 `Offer`, allowing any quantity up to a bound (lightningdevkit#4667).
* `lightning-custom-message` handlers that return `Ok(None)` when asked to
deserialize a message in their defined range no longer cause panics (lightningdevkit#4709).
* Several spurious debug assertions were fixed (lightningdevkit#4537, lightningdevkit#4618, lightningdevkit#4026)
Security
========
0.2.3 fixes several underestimates of the anchor reserves required to ensure we
can reliably close channels, several denial-of-service vulnerabilities and a
sanitization issue.
* `Bolt11Invoice::recover_payee_pub_key` no longer panics if called on an
invoice which set an explicit public key, rather than relying on public key
recovery. Note that this method is called from
`PaymentParameters::from_bolt11_invoice` (lightningdevkit#4717).
* Maliciously-crafted unpayable invoices which have overflowing feerates will
no longer cause an `unwrap` failure panic (lightningdevkit#4716).
* Parsing an `LSPSDateTime` which is before 1970 no longer panics. This is
reachable when parsing messages from counterparties (lightningdevkit#4715).
* `possiblyrandom` did not properly generate random data except when it was
explicitly configured to. By default this means LDK is vulnerable to various
HashDoS attacks (lightningdevkit#4719).
* `OMNameResolver` will no longer panic when looking up payment instructions
which include unicode characters at the start of a TXT record (lightningdevkit#4718).
* When using the `anchor_channel_reserves` module to calculate reserves
required to pay for fees when closing anchor channels, zero-fee-commitment
channels were not considered. This could allow a counterparty to open many
channels, leaving us unable to properly force-close (lightningdevkit#4592).
* The `anchor_channel_reserves` module overestimated the value of `Utxo`s in
the wallet by ignoring the `TxIn` cost to spend them (lightningdevkit#4670).
* `PrintableString` did not properly sanitize unicode format characters,
allowing an attacker to corrupt the rendering of logs or UI (lightningdevkit#4593, lightningdevkit#4605).
* RGS data is now limited in how large of a graph it is able to cause a client
to store in memory. Note that RGS data is still considered a DoS vector in
general and you should only use semi-trusted RGS data (lightningdevkit#4713).
* Counterparty-provided strings in failure messages are no longer logged in
full, reducing the ability of such a counterparty to spam our logs (lightningdevkit#4714).
* Reading a corrupted `ChannelManager` or `ProbabilisticScorer` can no longer
cause us to allocate large amounts of memory (lightningdevkit#4712).
Thanks to Project Loupe for reporting most of the issues fixed in this release.
Conflicts resolved in:
* lightning/src/chain/channelmonitor.rs
* lightning/src/events/mod.rs
* lightning/src/ln/channelmanager.rs
* lightning/src/ln/mod.rs
* lightning/src/ln/offers_tests.rs
* lightning/src/ln/onion_utils.rs
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Handle overflowing route-hint fee aggregates - #4716

Merged
TheBlueMatt merged 1 commit into
lightningdevkit:mainfrom
tnull:tnull/2026-05-fix-route-hint-overflow
Jun 18, 2026
Merged

Handle overflowing route-hint fee aggregates#4716
TheBlueMatt merged 1 commit into
lightningdevkit:mainfrom
tnull:tnull/2026-05-fix-route-hint-overflow

Conversation

@tnull

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Crafted route hints can overflow aggregate downstream proportional fees when the payer disables the routing fee cap. Treat such paths as unusable so route finding fails cleanly instead of panicking.

Reported by Project Loupe

Crafted route hints can overflow aggregate downstream proportional fees
when the payer disables the routing fee cap. Treat such paths as
unusable so route finding fails cleanly instead of panicking.
Co-Authored-By: HAL 9000
Signed-off-by: Elias Rohrer <dev@tnull.de>
@ldk-reviews-bot

ldk-reviews-bot commented Jun 18, 2026

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I've assigned @wpaulino as a reviewer!
I'll wait for their review and will help manage the review process.
Once they submit their review, I'll check if a second reviewer would be helpful.

@ldk-claude-review-bot

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No issues found.

I reviewed the entire diff and traced the supporting code paths:

  • max_final_value_msat now returns Result<(usize, u64), usize>, returning idx + 1 on aggregate-fee overflow. This index is always in bounds, since overflow can only occur when at least one downstream hop exists (compute_aggregated_base_prop_fee returns Ok((0,0)) for an empty iterator), so idx + 1 <= hops.len() - 1.
  • The get_route handler indexes payment_path.hops[candidate_idx_to_skip] safely, logs, marks the candidate exhausted, and continue 'paths_collection. used_liquidities persists across loop iterations, and add_entry saturating-subtracts the u64::MAX value to 0, excluding the candidate — so progress is guaranteed and no infinite loop occurs.
  • mark_candidate_liquidity_exhausted writes both (scid, false)/(scid, true) for clear hops and candidate.id() for the no-scid case, which is consistent with the keys read in max_final_value_msat (hop.candidate.id()) and add_entry ($candidate.id()).
  • The test correctly disables the fee cap (max_total_routing_fee_msat: None) and uses two route-hint hops with proportional_millionths: u32::MAX to trigger the overflow, asserting route.is_err().

Minor (non-blocking) cross-cutting note: the new mark_candidate_liquidity_exhausted helper overlaps with the inline scid-marking block at router.rs:3697-3700 (victim_candidate). Per the repo's DRY guidance that block could call the helper, though doing so would also add the no-scid/blinded else branch, which is a slight behavior change — so leaving it as-is is defensible.

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thanks

match payment_path.max_final_value_msat(&used_liquidities, channel_saturation_pow_half) {
Ok(contribution) => contribution,
Err(candidate_idx_to_skip) => {
let candidate = &payment_path.hops[candidate_idx_to_skip].0.candidate;

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The fact that this can't index OOB is incredibly subtle (compute_aggregated_base_prop_fee won't fail if next_hops_feerates_iter is empty, which will happen if we're at the end). Might be worth clarifying somewhere in a comment.

@TheBlueMatt
TheBlueMatt merged commit 61e3cab into lightningdevkit:mainJun 18, 2026
1 check passed
This was referenced Jun 18, 2026
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Backported to 0.2 in #4722.

@TheBlueMatt

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Backported to 0.1 in #4720.

TheBlueMatt added a commit that referenced this pull request Jun 19, 2026
v0.1.10 - Jun 18, 2026 - "Loupe de Loupe"
API Updates
===========
* `DefaultMessageRouter` will now always generate blinded message paths that
provide no privacy (where our node is the introduction node) for nodes with
public channels. This works around an issue which will appear for any nodes
with LND peers that enable onion messaging - such peers will refuse to
forward BOLT 12 messages from unknown third parties, which most BOLT 12
payers rely on today (#4647).
* Explicit `amount_msats` of 0 is rejected in BOLT 12 `Offer`s; `OfferBuilder`
now maps 0-amounts to an amount of `None` (#4324).
Bug Fixes
=========
* Async `ChannelMonitorUpdate` persistence operations which complete, but are
not marked as complete in a persisted `ChannelManager` prior to restart,
followed immediately by a block connection and then another restart could
result in some channel operations hanging leading for force-closures (#4377).
* If an MPP payment is claimed but `ChannelMonitorUpdate`s for some parts are
still being completed asynchronously, further channel updates (e.g.
forwarding another payment) are pending and the node restarts, the channel
could have become stuck (#4520).
* The presence of unconfirmed transactions actually no longer causes
`ElectrumSyncClient` to spuriously fail to sync (#4590).
* `FilesystemStore::list_all_keys` will no longer fail if there are stale
intermediate files lying around from a previous unclean shutdown (#4618).
* When forwarding an HTLC while in a blinded path with proportional fees over
200%, LDK will no longer spuriously allow a forward that pays us 1 msat too
little in fees (#4697).
* Fixed a rare case where a channel could get stuck on reconnect when using
both async `ChannelMonitorUpdate` persistence and async signing (#4684).
* `Event::PaymentSent::fee_paid_msat` is no longer `None` in cases where
`ChannelManager::abandon_payment` was called before the payment ultimately
completes anyway (#4651).
* Syncing a `ChainMonitor` using the `Confirm` trait will no longer write some
full `ChannelMonitor`s to disk several times per block (#4544).
* `OMDomainResolver` now correctly accounts for failed queries when rate
limiting, ensuring we continue to respond to queries after failures (#4591).
* Calling `ChannelManager::send_payment_with_route` without a `route_params`
and with an invalid `Route` will no longer panic (#4707).
* `lightning-custom-message`'s handling of `peer_connected` events now ensures
that sub-handlers will see a `peer_disconnected` event if a different
sub-handler refused the connection by `Err`ing `peer_connected` (#4595).
* Incomplete MPP keysend payments will no longer see their HTLCs held until
expiry (#4558).
* `InvoiceRequestBuilder` will no longer accept a `quantity` of `0` for a
BOLT 12 `Offer`, allowing any quantity up to a bound (#4667).
* `lightning-custom-message` handlers that return `Ok(None)` when asked to
deserialize a message in their defined range no longer cause panics (#4709).
* Several spurious debug assertions were fixed (#4537, #4618).
Security
========
0.1.10 fixes a sanitization issue and several denial-of-service vulnerabilities.
* `Bolt11Invoice::recover_payee_pub_key` no longer panics if called on an
invoice which set an explicit public key, rather than relying on public key
recovery. This method is called from `payment_parameters_from_invoice` and
`payment_parameters_from_variable_amount_invoice` (#4717).
* Maliciously-crafted unpayable invoices which have overflowing feerates will
no longer cause an `unwrap` failure panic (#4716).
* `possiblyrandom` did not properly generate random data except when it was
explicitly configured to. By default this means LDK is vulnerable to various
HashDoS attacks (#4719).
* `OMNameResolver` will no longer panic when looking up payment instructions
which include unicode characters at the start of a TXT record (#4718).
* `PrintableString` did not properly sanitize unicode format characters,
allowing an attacker to corrupt the rendering of logs or UI (#4593, #4605).
* RGS data is now limited in how large of a graph it is able to cause a client
to store in memory. Note that RGS data is still considered a DoS vector in
general and you should only use semi-trusted RGS data (#4713).
* Counterparty-provided strings in failure messages are no longer logged in
full, reducing the ability of such a counterparty to spam our logs (#4714).
* Reading a corrupted `ChannelManager` or `ProbabilisticScorer` can no longer
cause us to allocate large amounts of memory (#4712).
Thanks to Project Loupe for reporting most of the issues fixed in this release.
TheBlueMatt added a commit to TheBlueMatt/rust-lightning that referenced this pull request Jun 23, 2026
v0.2.3 - Jun 18, 2026 - "Through the Loupe"
API Updates
===========
* `DefaultMessageRouter` will now always generate blinded message paths that
provide no privacy (where our node is the introduction node) for nodes with
public channels. This works around an issue which will appear for any nodes
with LND peers that enable onion messaging - such peers will refuse to
forward BOLT 12 messages from unknown third parties, which most BOLT 12
payers rely on today (lightningdevkit#4647).
* Explicit `amount_msats` of 0 is rejected in BOLT 12 `Offer`s; `OfferBuilder`
now maps 0-amounts to an amount of `None` (lightningdevkit#4324).
Bug Fixes
=========
* `Features::supports_zero_conf` no longer clears the `ZeroConf` features and
`Features::requires_zero_conf` now correctly reports required, rather than
supported, status (lightningdevkit#4517).
* If an MPP payment is claimed but `ChannelMonitorUpdate`s for some parts are
still being completed asynchronously, further channel updates (e.g.
forwarding another payment) are pending and the node restarts, the channel
could have become stuck (lightningdevkit#4520).
* The presence of unconfirmed transactions actually no longer causes
`ElectrumSyncClient` to spuriously fail to sync (lightningdevkit#4590).
* LSPS1, LSPS2, and LSPS5 persistence will no longer get stuck and refuse to
persist again after a single failure from the KVStore (lightningdevkit#4597, lightningdevkit#4282).
* Dropping the future returned by
`OutputSweeper::regenerate_and_broadcast_spend_if_necessary` no longer
results in future calls to the same method being spuriously ignored (lightningdevkit#4598).
* Used async-receive offers are no longer refreshed on every timer tick once
their refresh time is reached (lightningdevkit#4672).
* `FilesystemStore::list_all_keys` will no longer fail if there are stale
intermediate files lying around from a previous unclean shutdown (lightningdevkit#4618).
* When forwarding an HTLC while in a blinded path with proportional fees over
200%, LDK will no longer spuriously allow a forward that pays us 1 msat too
little in fees (lightningdevkit#4697).
* Fixed a rare case where a channel could get stuck on reconnect when using
both async `ChannelMonitorUpdate` persistence and async signing (lightningdevkit#4684).
* If we had exactly zero balance in a zero-fee-commitment channel, the
counterparty was able to splice all of their balance out, violating the
reserve requirements they'd otherwise be forced to keep (lightningdevkit#4580).
* Providing an `Event::HTLCIntercepted` to the `LSPS2ServiceHandler` twice no
longer results in spuriously opening a channel early (lightningdevkit#4656).
* `Event::PaymentSent::fee_paid_msat` is no longer `None` in cases where
`ChannelManager::abandon_payment` was called before the payment ultimately
completes anyway (lightningdevkit#4651).
* `AnchorDescriptor::previous_utxo` now provides the correct `script_pubkey`
for non-zero-commitment-fee anchor channels (lightningdevkit#4669).
* Syncing a `ChainMonitor` using the `Confirm` trait will no longer write some
full `ChannelMonitor`s to disk several times per block (lightningdevkit#4544).
* `OMDomainResolver` now correctly accounts for failed queries when rate
limiting, ensuring we continue to respond to queries after failures (lightningdevkit#4591).
* Calling `ChannelManager::send_payment_with_route` without a `route_params`
and with an invalid `Route` will no longer panic (lightningdevkit#4707).
* `LSPS2ServiceHandler::channel_open_failed` now correctly fails intercepted
HTLCs rather than allowing them to fail just before expiry (lightningdevkit#4677).
* `StaticInvoice::is_offer_expired` was corrected to check offer, rather than
static invoice, expiry (lightningdevkit#4594).
* `lightning-custom-message`'s handling of `peer_connected` events now ensures
that sub-handlers will see a `peer_disconnected` event if a different
sub-handler refused the connection by `Err`ing `peer_connected` (lightningdevkit#4595).
* Replay protection for LSPS5 signatures now detects replays which are only
different in the encoded signature's case (lightningdevkit#4701).
* When `lightning-liquidity` is configured in the background processor, there
is no longer a stream of `Persisting LiquidityManager...` log spam (lightningdevkit#4246).
* Incomplete MPP keysend payments will no longer see their HTLCs held until
expiry (lightningdevkit#4558).
* `InvoiceRequestBuilder` will no longer accept a `quantity` of `0` for a
BOLT 12 `Offer`, allowing any quantity up to a bound (lightningdevkit#4667).
* `lightning-custom-message` handlers that return `Ok(None)` when asked to
deserialize a message in their defined range no longer cause panics (lightningdevkit#4709).
* Several spurious debug assertions were fixed (lightningdevkit#4537, lightningdevkit#4618, lightningdevkit#4026)
Security
========
0.2.3 fixes several underestimates of the anchor reserves required to ensure we
can reliably close channels, several denial-of-service vulnerabilities and a
sanitization issue.
* `Bolt11Invoice::recover_payee_pub_key` no longer panics if called on an
invoice which set an explicit public key, rather than relying on public key
recovery. Note that this method is called from
`PaymentParameters::from_bolt11_invoice` (lightningdevkit#4717).
* Maliciously-crafted unpayable invoices which have overflowing feerates will
no longer cause an `unwrap` failure panic (lightningdevkit#4716).
* Parsing an `LSPSDateTime` which is before 1970 no longer panics. This is
reachable when parsing messages from counterparties (lightningdevkit#4715).
* `possiblyrandom` did not properly generate random data except when it was
explicitly configured to. By default this means LDK is vulnerable to various
HashDoS attacks (lightningdevkit#4719).
* `OMNameResolver` will no longer panic when looking up payment instructions
which include unicode characters at the start of a TXT record (lightningdevkit#4718).
* When using the `anchor_channel_reserves` module to calculate reserves
required to pay for fees when closing anchor channels, zero-fee-commitment
channels were not considered. This could allow a counterparty to open many
channels, leaving us unable to properly force-close (lightningdevkit#4592).
* The `anchor_channel_reserves` module overestimated the value of `Utxo`s in
the wallet by ignoring the `TxIn` cost to spend them (lightningdevkit#4670).
* `PrintableString` did not properly sanitize unicode format characters,
allowing an attacker to corrupt the rendering of logs or UI (lightningdevkit#4593, lightningdevkit#4605).
* RGS data is now limited in how large of a graph it is able to cause a client
to store in memory. Note that RGS data is still considered a DoS vector in
general and you should only use semi-trusted RGS data (lightningdevkit#4713).
* Counterparty-provided strings in failure messages are no longer logged in
full, reducing the ability of such a counterparty to spam our logs (lightningdevkit#4714).
* Reading a corrupted `ChannelManager` or `ProbabilisticScorer` can no longer
cause us to allocate large amounts of memory (lightningdevkit#4712).
Thanks to Project Loupe for reporting most of the issues fixed in this release.
Conflicts resolved in:
* lightning/src/chain/channelmonitor.rs
* lightning/src/events/mod.rs
* lightning/src/ln/channelmanager.rs
* lightning/src/ln/mod.rs
* lightning/src/ln/offers_tests.rs
* lightning/src/ln/onion_utils.rs
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@tnull@ldk-reviews-bot@ldk-claude-review-bot@TheBlueMatt
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Handle overflowing route-hint fee aggregates - #4716

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TheBlueMatt merged 1 commit into
lightningdevkit:mainfrom
tnull:tnull/2026-05-fix-route-hint-overflow
Jun 18, 2026
Merged

Handle overflowing route-hint fee aggregates#4716
TheBlueMatt merged 1 commit into
lightningdevkit:mainfrom
tnull:tnull/2026-05-fix-route-hint-overflow

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Crafted route hints can overflow aggregate downstream proportional fees when the payer disables the routing fee cap. Treat such paths as unusable so route finding fails cleanly instead of panicking.

Reported by Project Loupe

Crafted route hints can overflow aggregate downstream proportional fees
when the payer disables the routing fee cap. Treat such paths as
unusable so route finding fails cleanly instead of panicking.
Co-Authored-By: HAL 9000
Signed-off-by: Elias Rohrer <dev@tnull.de>
@ldk-reviews-bot

ldk-reviews-bot commented Jun 18, 2026

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I've assigned @wpaulino as a reviewer!
I'll wait for their review and will help manage the review process.
Once they submit their review, I'll check if a second reviewer would be helpful.

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No issues found.

I reviewed the entire diff and traced the supporting code paths:

  • max_final_value_msat now returns Result<(usize, u64), usize>, returning idx + 1 on aggregate-fee overflow. This index is always in bounds, since overflow can only occur when at least one downstream hop exists (compute_aggregated_base_prop_fee returns Ok((0,0)) for an empty iterator), so idx + 1 <= hops.len() - 1.
  • The get_route handler indexes payment_path.hops[candidate_idx_to_skip] safely, logs, marks the candidate exhausted, and continue 'paths_collection. used_liquidities persists across loop iterations, and add_entry saturating-subtracts the u64::MAX value to 0, excluding the candidate — so progress is guaranteed and no infinite loop occurs.
  • mark_candidate_liquidity_exhausted writes both (scid, false)/(scid, true) for clear hops and candidate.id() for the no-scid case, which is consistent with the keys read in max_final_value_msat (hop.candidate.id()) and add_entry ($candidate.id()).
  • The test correctly disables the fee cap (max_total_routing_fee_msat: None) and uses two route-hint hops with proportional_millionths: u32::MAX to trigger the overflow, asserting route.is_err().

Minor (non-blocking) cross-cutting note: the new mark_candidate_liquidity_exhausted helper overlaps with the inline scid-marking block at router.rs:3697-3700 (victim_candidate). Per the repo's DRY guidance that block could call the helper, though doing so would also add the no-scid/blinded else branch, which is a slight behavior change — so leaving it as-is is defensible.

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thanks

match payment_path.max_final_value_msat(&used_liquidities, channel_saturation_pow_half) {
Ok(contribution) => contribution,
Err(candidate_idx_to_skip) => {
let candidate = &payment_path.hops[candidate_idx_to_skip].0.candidate;

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The fact that this can't index OOB is incredibly subtle (compute_aggregated_base_prop_fee won't fail if next_hops_feerates_iter is empty, which will happen if we're at the end). Might be worth clarifying somewhere in a comment.

@TheBlueMatt
TheBlueMatt merged commit 61e3cab into lightningdevkit:mainJun 18, 2026
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This was referenced Jun 18, 2026
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Backported to 0.2 in #4722.

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Backported to 0.1 in #4720.

TheBlueMatt added a commit that referenced this pull request Jun 19, 2026
v0.1.10 - Jun 18, 2026 - "Loupe de Loupe"
API Updates
===========
* `DefaultMessageRouter` will now always generate blinded message paths that
provide no privacy (where our node is the introduction node) for nodes with
public channels. This works around an issue which will appear for any nodes
with LND peers that enable onion messaging - such peers will refuse to
forward BOLT 12 messages from unknown third parties, which most BOLT 12
payers rely on today (#4647).
* Explicit `amount_msats` of 0 is rejected in BOLT 12 `Offer`s; `OfferBuilder`
now maps 0-amounts to an amount of `None` (#4324).
Bug Fixes
=========
* Async `ChannelMonitorUpdate` persistence operations which complete, but are
not marked as complete in a persisted `ChannelManager` prior to restart,
followed immediately by a block connection and then another restart could
result in some channel operations hanging leading for force-closures (#4377).
* If an MPP payment is claimed but `ChannelMonitorUpdate`s for some parts are
still being completed asynchronously, further channel updates (e.g.
forwarding another payment) are pending and the node restarts, the channel
could have become stuck (#4520).
* The presence of unconfirmed transactions actually no longer causes
`ElectrumSyncClient` to spuriously fail to sync (#4590).
* `FilesystemStore::list_all_keys` will no longer fail if there are stale
intermediate files lying around from a previous unclean shutdown (#4618).
* When forwarding an HTLC while in a blinded path with proportional fees over
200%, LDK will no longer spuriously allow a forward that pays us 1 msat too
little in fees (#4697).
* Fixed a rare case where a channel could get stuck on reconnect when using
both async `ChannelMonitorUpdate` persistence and async signing (#4684).
* `Event::PaymentSent::fee_paid_msat` is no longer `None` in cases where
`ChannelManager::abandon_payment` was called before the payment ultimately
completes anyway (#4651).
* Syncing a `ChainMonitor` using the `Confirm` trait will no longer write some
full `ChannelMonitor`s to disk several times per block (#4544).
* `OMDomainResolver` now correctly accounts for failed queries when rate
limiting, ensuring we continue to respond to queries after failures (#4591).
* Calling `ChannelManager::send_payment_with_route` without a `route_params`
and with an invalid `Route` will no longer panic (#4707).
* `lightning-custom-message`'s handling of `peer_connected` events now ensures
that sub-handlers will see a `peer_disconnected` event if a different
sub-handler refused the connection by `Err`ing `peer_connected` (#4595).
* Incomplete MPP keysend payments will no longer see their HTLCs held until
expiry (#4558).
* `InvoiceRequestBuilder` will no longer accept a `quantity` of `0` for a
BOLT 12 `Offer`, allowing any quantity up to a bound (#4667).
* `lightning-custom-message` handlers that return `Ok(None)` when asked to
deserialize a message in their defined range no longer cause panics (#4709).
* Several spurious debug assertions were fixed (#4537, #4618).
Security
========
0.1.10 fixes a sanitization issue and several denial-of-service vulnerabilities.
* `Bolt11Invoice::recover_payee_pub_key` no longer panics if called on an
invoice which set an explicit public key, rather than relying on public key
recovery. This method is called from `payment_parameters_from_invoice` and
`payment_parameters_from_variable_amount_invoice` (#4717).
* Maliciously-crafted unpayable invoices which have overflowing feerates will
no longer cause an `unwrap` failure panic (#4716).
* `possiblyrandom` did not properly generate random data except when it was
explicitly configured to. By default this means LDK is vulnerable to various
HashDoS attacks (#4719).
* `OMNameResolver` will no longer panic when looking up payment instructions
which include unicode characters at the start of a TXT record (#4718).
* `PrintableString` did not properly sanitize unicode format characters,
allowing an attacker to corrupt the rendering of logs or UI (#4593, #4605).
* RGS data is now limited in how large of a graph it is able to cause a client
to store in memory. Note that RGS data is still considered a DoS vector in
general and you should only use semi-trusted RGS data (#4713).
* Counterparty-provided strings in failure messages are no longer logged in
full, reducing the ability of such a counterparty to spam our logs (#4714).
* Reading a corrupted `ChannelManager` or `ProbabilisticScorer` can no longer
cause us to allocate large amounts of memory (#4712).
Thanks to Project Loupe for reporting most of the issues fixed in this release.
TheBlueMatt added a commit to TheBlueMatt/rust-lightning that referenced this pull request Jun 23, 2026
v0.2.3 - Jun 18, 2026 - "Through the Loupe"
API Updates
===========
* `DefaultMessageRouter` will now always generate blinded message paths that
provide no privacy (where our node is the introduction node) for nodes with
public channels. This works around an issue which will appear for any nodes
with LND peers that enable onion messaging - such peers will refuse to
forward BOLT 12 messages from unknown third parties, which most BOLT 12
payers rely on today (lightningdevkit#4647).
* Explicit `amount_msats` of 0 is rejected in BOLT 12 `Offer`s; `OfferBuilder`
now maps 0-amounts to an amount of `None` (lightningdevkit#4324).
Bug Fixes
=========
* `Features::supports_zero_conf` no longer clears the `ZeroConf` features and
`Features::requires_zero_conf` now correctly reports required, rather than
supported, status (lightningdevkit#4517).
* If an MPP payment is claimed but `ChannelMonitorUpdate`s for some parts are
still being completed asynchronously, further channel updates (e.g.
forwarding another payment) are pending and the node restarts, the channel
could have become stuck (lightningdevkit#4520).
* The presence of unconfirmed transactions actually no longer causes
`ElectrumSyncClient` to spuriously fail to sync (lightningdevkit#4590).
* LSPS1, LSPS2, and LSPS5 persistence will no longer get stuck and refuse to
persist again after a single failure from the KVStore (lightningdevkit#4597, lightningdevkit#4282).
* Dropping the future returned by
`OutputSweeper::regenerate_and_broadcast_spend_if_necessary` no longer
results in future calls to the same method being spuriously ignored (lightningdevkit#4598).
* Used async-receive offers are no longer refreshed on every timer tick once
their refresh time is reached (lightningdevkit#4672).
* `FilesystemStore::list_all_keys` will no longer fail if there are stale
intermediate files lying around from a previous unclean shutdown (lightningdevkit#4618).
* When forwarding an HTLC while in a blinded path with proportional fees over
200%, LDK will no longer spuriously allow a forward that pays us 1 msat too
little in fees (lightningdevkit#4697).
* Fixed a rare case where a channel could get stuck on reconnect when using
both async `ChannelMonitorUpdate` persistence and async signing (lightningdevkit#4684).
* If we had exactly zero balance in a zero-fee-commitment channel, the
counterparty was able to splice all of their balance out, violating the
reserve requirements they'd otherwise be forced to keep (lightningdevkit#4580).
* Providing an `Event::HTLCIntercepted` to the `LSPS2ServiceHandler` twice no
longer results in spuriously opening a channel early (lightningdevkit#4656).
* `Event::PaymentSent::fee_paid_msat` is no longer `None` in cases where
`ChannelManager::abandon_payment` was called before the payment ultimately
completes anyway (lightningdevkit#4651).
* `AnchorDescriptor::previous_utxo` now provides the correct `script_pubkey`
for non-zero-commitment-fee anchor channels (lightningdevkit#4669).
* Syncing a `ChainMonitor` using the `Confirm` trait will no longer write some
full `ChannelMonitor`s to disk several times per block (lightningdevkit#4544).
* `OMDomainResolver` now correctly accounts for failed queries when rate
limiting, ensuring we continue to respond to queries after failures (lightningdevkit#4591).
* Calling `ChannelManager::send_payment_with_route` without a `route_params`
and with an invalid `Route` will no longer panic (lightningdevkit#4707).
* `LSPS2ServiceHandler::channel_open_failed` now correctly fails intercepted
HTLCs rather than allowing them to fail just before expiry (lightningdevkit#4677).
* `StaticInvoice::is_offer_expired` was corrected to check offer, rather than
static invoice, expiry (lightningdevkit#4594).
* `lightning-custom-message`'s handling of `peer_connected` events now ensures
that sub-handlers will see a `peer_disconnected` event if a different
sub-handler refused the connection by `Err`ing `peer_connected` (lightningdevkit#4595).
* Replay protection for LSPS5 signatures now detects replays which are only
different in the encoded signature's case (lightningdevkit#4701).
* When `lightning-liquidity` is configured in the background processor, there
is no longer a stream of `Persisting LiquidityManager...` log spam (lightningdevkit#4246).
* Incomplete MPP keysend payments will no longer see their HTLCs held until
expiry (lightningdevkit#4558).
* `InvoiceRequestBuilder` will no longer accept a `quantity` of `0` for a
BOLT 12 `Offer`, allowing any quantity up to a bound (lightningdevkit#4667).
* `lightning-custom-message` handlers that return `Ok(None)` when asked to
deserialize a message in their defined range no longer cause panics (lightningdevkit#4709).
* Several spurious debug assertions were fixed (lightningdevkit#4537, lightningdevkit#4618, lightningdevkit#4026)
Security
========
0.2.3 fixes several underestimates of the anchor reserves required to ensure we
can reliably close channels, several denial-of-service vulnerabilities and a
sanitization issue.
* `Bolt11Invoice::recover_payee_pub_key` no longer panics if called on an
invoice which set an explicit public key, rather than relying on public key
recovery. Note that this method is called from
`PaymentParameters::from_bolt11_invoice` (lightningdevkit#4717).
* Maliciously-crafted unpayable invoices which have overflowing feerates will
no longer cause an `unwrap` failure panic (lightningdevkit#4716).
* Parsing an `LSPSDateTime` which is before 1970 no longer panics. This is
reachable when parsing messages from counterparties (lightningdevkit#4715).
* `possiblyrandom` did not properly generate random data except when it was
explicitly configured to. By default this means LDK is vulnerable to various
HashDoS attacks (lightningdevkit#4719).
* `OMNameResolver` will no longer panic when looking up payment instructions
which include unicode characters at the start of a TXT record (lightningdevkit#4718).
* When using the `anchor_channel_reserves` module to calculate reserves
required to pay for fees when closing anchor channels, zero-fee-commitment
channels were not considered. This could allow a counterparty to open many
channels, leaving us unable to properly force-close (lightningdevkit#4592).
* The `anchor_channel_reserves` module overestimated the value of `Utxo`s in
the wallet by ignoring the `TxIn` cost to spend them (lightningdevkit#4670).
* `PrintableString` did not properly sanitize unicode format characters,
allowing an attacker to corrupt the rendering of logs or UI (lightningdevkit#4593, lightningdevkit#4605).
* RGS data is now limited in how large of a graph it is able to cause a client
to store in memory. Note that RGS data is still considered a DoS vector in
general and you should only use semi-trusted RGS data (lightningdevkit#4713).
* Counterparty-provided strings in failure messages are no longer logged in
full, reducing the ability of such a counterparty to spam our logs (lightningdevkit#4714).
* Reading a corrupted `ChannelManager` or `ProbabilisticScorer` can no longer
cause us to allocate large amounts of memory (lightningdevkit#4712).
Thanks to Project Loupe for reporting most of the issues fixed in this release.
Conflicts resolved in:
* lightning/src/chain/channelmonitor.rs
* lightning/src/events/mod.rs
* lightning/src/ln/channelmanager.rs
* lightning/src/ln/mod.rs
* lightning/src/ln/offers_tests.rs
* lightning/src/ln/onion_utils.rs
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Handle overflowing route-hint fee aggregates - #4716

Merged
TheBlueMatt merged 1 commit into
lightningdevkit:mainfrom
tnull:tnull/2026-05-fix-route-hint-overflow
Jun 18, 2026
Merged

Handle overflowing route-hint fee aggregates#4716
TheBlueMatt merged 1 commit into
lightningdevkit:mainfrom
tnull:tnull/2026-05-fix-route-hint-overflow

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Crafted route hints can overflow aggregate downstream proportional fees when the payer disables the routing fee cap. Treat such paths as unusable so route finding fails cleanly instead of panicking.

Reported by Project Loupe

Crafted route hints can overflow aggregate downstream proportional fees
when the payer disables the routing fee cap. Treat such paths as
unusable so route finding fails cleanly instead of panicking.
Co-Authored-By: HAL 9000
Signed-off-by: Elias Rohrer <dev@tnull.de>
@ldk-reviews-bot

ldk-reviews-bot commented Jun 18, 2026

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I've assigned @wpaulino as a reviewer!
I'll wait for their review and will help manage the review process.
Once they submit their review, I'll check if a second reviewer would be helpful.

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No issues found.

I reviewed the entire diff and traced the supporting code paths:

  • max_final_value_msat now returns Result<(usize, u64), usize>, returning idx + 1 on aggregate-fee overflow. This index is always in bounds, since overflow can only occur when at least one downstream hop exists (compute_aggregated_base_prop_fee returns Ok((0,0)) for an empty iterator), so idx + 1 <= hops.len() - 1.
  • The get_route handler indexes payment_path.hops[candidate_idx_to_skip] safely, logs, marks the candidate exhausted, and continue 'paths_collection. used_liquidities persists across loop iterations, and add_entry saturating-subtracts the u64::MAX value to 0, excluding the candidate — so progress is guaranteed and no infinite loop occurs.
  • mark_candidate_liquidity_exhausted writes both (scid, false)/(scid, true) for clear hops and candidate.id() for the no-scid case, which is consistent with the keys read in max_final_value_msat (hop.candidate.id()) and add_entry ($candidate.id()).
  • The test correctly disables the fee cap (max_total_routing_fee_msat: None) and uses two route-hint hops with proportional_millionths: u32::MAX to trigger the overflow, asserting route.is_err().

Minor (non-blocking) cross-cutting note: the new mark_candidate_liquidity_exhausted helper overlaps with the inline scid-marking block at router.rs:3697-3700 (victim_candidate). Per the repo's DRY guidance that block could call the helper, though doing so would also add the no-scid/blinded else branch, which is a slight behavior change — so leaving it as-is is defensible.

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thanks

match payment_path.max_final_value_msat(&used_liquidities, channel_saturation_pow_half) {
Ok(contribution) => contribution,
Err(candidate_idx_to_skip) => {
let candidate = &payment_path.hops[candidate_idx_to_skip].0.candidate;

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The fact that this can't index OOB is incredibly subtle (compute_aggregated_base_prop_fee won't fail if next_hops_feerates_iter is empty, which will happen if we're at the end). Might be worth clarifying somewhere in a comment.

@TheBlueMatt
TheBlueMatt merged commit 61e3cab into lightningdevkit:mainJun 18, 2026
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This was referenced Jun 18, 2026
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Backported to 0.2 in #4722.

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Backported to 0.1 in #4720.

TheBlueMatt added a commit that referenced this pull request Jun 19, 2026
v0.1.10 - Jun 18, 2026 - "Loupe de Loupe"
API Updates
===========
* `DefaultMessageRouter` will now always generate blinded message paths that
provide no privacy (where our node is the introduction node) for nodes with
public channels. This works around an issue which will appear for any nodes
with LND peers that enable onion messaging - such peers will refuse to
forward BOLT 12 messages from unknown third parties, which most BOLT 12
payers rely on today (#4647).
* Explicit `amount_msats` of 0 is rejected in BOLT 12 `Offer`s; `OfferBuilder`
now maps 0-amounts to an amount of `None` (#4324).
Bug Fixes
=========
* Async `ChannelMonitorUpdate` persistence operations which complete, but are
not marked as complete in a persisted `ChannelManager` prior to restart,
followed immediately by a block connection and then another restart could
result in some channel operations hanging leading for force-closures (#4377).
* If an MPP payment is claimed but `ChannelMonitorUpdate`s for some parts are
still being completed asynchronously, further channel updates (e.g.
forwarding another payment) are pending and the node restarts, the channel
could have become stuck (#4520).
* The presence of unconfirmed transactions actually no longer causes
`ElectrumSyncClient` to spuriously fail to sync (#4590).
* `FilesystemStore::list_all_keys` will no longer fail if there are stale
intermediate files lying around from a previous unclean shutdown (#4618).
* When forwarding an HTLC while in a blinded path with proportional fees over
200%, LDK will no longer spuriously allow a forward that pays us 1 msat too
little in fees (#4697).
* Fixed a rare case where a channel could get stuck on reconnect when using
both async `ChannelMonitorUpdate` persistence and async signing (#4684).
* `Event::PaymentSent::fee_paid_msat` is no longer `None` in cases where
`ChannelManager::abandon_payment` was called before the payment ultimately
completes anyway (#4651).
* Syncing a `ChainMonitor` using the `Confirm` trait will no longer write some
full `ChannelMonitor`s to disk several times per block (#4544).
* `OMDomainResolver` now correctly accounts for failed queries when rate
limiting, ensuring we continue to respond to queries after failures (#4591).
* Calling `ChannelManager::send_payment_with_route` without a `route_params`
and with an invalid `Route` will no longer panic (#4707).
* `lightning-custom-message`'s handling of `peer_connected` events now ensures
that sub-handlers will see a `peer_disconnected` event if a different
sub-handler refused the connection by `Err`ing `peer_connected` (#4595).
* Incomplete MPP keysend payments will no longer see their HTLCs held until
expiry (#4558).
* `InvoiceRequestBuilder` will no longer accept a `quantity` of `0` for a
BOLT 12 `Offer`, allowing any quantity up to a bound (#4667).
* `lightning-custom-message` handlers that return `Ok(None)` when asked to
deserialize a message in their defined range no longer cause panics (#4709).
* Several spurious debug assertions were fixed (#4537, #4618).
Security
========
0.1.10 fixes a sanitization issue and several denial-of-service vulnerabilities.
* `Bolt11Invoice::recover_payee_pub_key` no longer panics if called on an
invoice which set an explicit public key, rather than relying on public key
recovery. This method is called from `payment_parameters_from_invoice` and
`payment_parameters_from_variable_amount_invoice` (#4717).
* Maliciously-crafted unpayable invoices which have overflowing feerates will
no longer cause an `unwrap` failure panic (#4716).
* `possiblyrandom` did not properly generate random data except when it was
explicitly configured to. By default this means LDK is vulnerable to various
HashDoS attacks (#4719).
* `OMNameResolver` will no longer panic when looking up payment instructions
which include unicode characters at the start of a TXT record (#4718).
* `PrintableString` did not properly sanitize unicode format characters,
allowing an attacker to corrupt the rendering of logs or UI (#4593, #4605).
* RGS data is now limited in how large of a graph it is able to cause a client
to store in memory. Note that RGS data is still considered a DoS vector in
general and you should only use semi-trusted RGS data (#4713).
* Counterparty-provided strings in failure messages are no longer logged in
full, reducing the ability of such a counterparty to spam our logs (#4714).
* Reading a corrupted `ChannelManager` or `ProbabilisticScorer` can no longer
cause us to allocate large amounts of memory (#4712).
Thanks to Project Loupe for reporting most of the issues fixed in this release.
TheBlueMatt added a commit to TheBlueMatt/rust-lightning that referenced this pull request Jun 23, 2026
v0.2.3 - Jun 18, 2026 - "Through the Loupe"
API Updates
===========
* `DefaultMessageRouter` will now always generate blinded message paths that
provide no privacy (where our node is the introduction node) for nodes with
public channels. This works around an issue which will appear for any nodes
with LND peers that enable onion messaging - such peers will refuse to
forward BOLT 12 messages from unknown third parties, which most BOLT 12
payers rely on today (lightningdevkit#4647).
* Explicit `amount_msats` of 0 is rejected in BOLT 12 `Offer`s; `OfferBuilder`
now maps 0-amounts to an amount of `None` (lightningdevkit#4324).
Bug Fixes
=========
* `Features::supports_zero_conf` no longer clears the `ZeroConf` features and
`Features::requires_zero_conf` now correctly reports required, rather than
supported, status (lightningdevkit#4517).
* If an MPP payment is claimed but `ChannelMonitorUpdate`s for some parts are
still being completed asynchronously, further channel updates (e.g.
forwarding another payment) are pending and the node restarts, the channel
could have become stuck (lightningdevkit#4520).
* The presence of unconfirmed transactions actually no longer causes
`ElectrumSyncClient` to spuriously fail to sync (lightningdevkit#4590).
* LSPS1, LSPS2, and LSPS5 persistence will no longer get stuck and refuse to
persist again after a single failure from the KVStore (lightningdevkit#4597, lightningdevkit#4282).
* Dropping the future returned by
`OutputSweeper::regenerate_and_broadcast_spend_if_necessary` no longer
results in future calls to the same method being spuriously ignored (lightningdevkit#4598).
* Used async-receive offers are no longer refreshed on every timer tick once
their refresh time is reached (lightningdevkit#4672).
* `FilesystemStore::list_all_keys` will no longer fail if there are stale
intermediate files lying around from a previous unclean shutdown (lightningdevkit#4618).
* When forwarding an HTLC while in a blinded path with proportional fees over
200%, LDK will no longer spuriously allow a forward that pays us 1 msat too
little in fees (lightningdevkit#4697).
* Fixed a rare case where a channel could get stuck on reconnect when using
both async `ChannelMonitorUpdate` persistence and async signing (lightningdevkit#4684).
* If we had exactly zero balance in a zero-fee-commitment channel, the
counterparty was able to splice all of their balance out, violating the
reserve requirements they'd otherwise be forced to keep (lightningdevkit#4580).
* Providing an `Event::HTLCIntercepted` to the `LSPS2ServiceHandler` twice no
longer results in spuriously opening a channel early (lightningdevkit#4656).
* `Event::PaymentSent::fee_paid_msat` is no longer `None` in cases where
`ChannelManager::abandon_payment` was called before the payment ultimately
completes anyway (lightningdevkit#4651).
* `AnchorDescriptor::previous_utxo` now provides the correct `script_pubkey`
for non-zero-commitment-fee anchor channels (lightningdevkit#4669).
* Syncing a `ChainMonitor` using the `Confirm` trait will no longer write some
full `ChannelMonitor`s to disk several times per block (lightningdevkit#4544).
* `OMDomainResolver` now correctly accounts for failed queries when rate
limiting, ensuring we continue to respond to queries after failures (lightningdevkit#4591).
* Calling `ChannelManager::send_payment_with_route` without a `route_params`
and with an invalid `Route` will no longer panic (lightningdevkit#4707).
* `LSPS2ServiceHandler::channel_open_failed` now correctly fails intercepted
HTLCs rather than allowing them to fail just before expiry (lightningdevkit#4677).
* `StaticInvoice::is_offer_expired` was corrected to check offer, rather than
static invoice, expiry (lightningdevkit#4594).
* `lightning-custom-message`'s handling of `peer_connected` events now ensures
that sub-handlers will see a `peer_disconnected` event if a different
sub-handler refused the connection by `Err`ing `peer_connected` (lightningdevkit#4595).
* Replay protection for LSPS5 signatures now detects replays which are only
different in the encoded signature's case (lightningdevkit#4701).
* When `lightning-liquidity` is configured in the background processor, there
is no longer a stream of `Persisting LiquidityManager...` log spam (lightningdevkit#4246).
* Incomplete MPP keysend payments will no longer see their HTLCs held until
expiry (lightningdevkit#4558).
* `InvoiceRequestBuilder` will no longer accept a `quantity` of `0` for a
BOLT 12 `Offer`, allowing any quantity up to a bound (lightningdevkit#4667).
* `lightning-custom-message` handlers that return `Ok(None)` when asked to
deserialize a message in their defined range no longer cause panics (lightningdevkit#4709).
* Several spurious debug assertions were fixed (lightningdevkit#4537, lightningdevkit#4618, lightningdevkit#4026)
Security
========
0.2.3 fixes several underestimates of the anchor reserves required to ensure we
can reliably close channels, several denial-of-service vulnerabilities and a
sanitization issue.
* `Bolt11Invoice::recover_payee_pub_key` no longer panics if called on an
invoice which set an explicit public key, rather than relying on public key
recovery. Note that this method is called from
`PaymentParameters::from_bolt11_invoice` (lightningdevkit#4717).
* Maliciously-crafted unpayable invoices which have overflowing feerates will
no longer cause an `unwrap` failure panic (lightningdevkit#4716).
* Parsing an `LSPSDateTime` which is before 1970 no longer panics. This is
reachable when parsing messages from counterparties (lightningdevkit#4715).
* `possiblyrandom` did not properly generate random data except when it was
explicitly configured to. By default this means LDK is vulnerable to various
HashDoS attacks (lightningdevkit#4719).
* `OMNameResolver` will no longer panic when looking up payment instructions
which include unicode characters at the start of a TXT record (lightningdevkit#4718).
* When using the `anchor_channel_reserves` module to calculate reserves
required to pay for fees when closing anchor channels, zero-fee-commitment
channels were not considered. This could allow a counterparty to open many
channels, leaving us unable to properly force-close (lightningdevkit#4592).
* The `anchor_channel_reserves` module overestimated the value of `Utxo`s in
the wallet by ignoring the `TxIn` cost to spend them (lightningdevkit#4670).
* `PrintableString` did not properly sanitize unicode format characters,
allowing an attacker to corrupt the rendering of logs or UI (lightningdevkit#4593, lightningdevkit#4605).
* RGS data is now limited in how large of a graph it is able to cause a client
to store in memory. Note that RGS data is still considered a DoS vector in
general and you should only use semi-trusted RGS data (lightningdevkit#4713).
* Counterparty-provided strings in failure messages are no longer logged in
full, reducing the ability of such a counterparty to spam our logs (lightningdevkit#4714).
* Reading a corrupted `ChannelManager` or `ProbabilisticScorer` can no longer
cause us to allocate large amounts of memory (lightningdevkit#4712).
Thanks to Project Loupe for reporting most of the issues fixed in this release.
Conflicts resolved in:
* lightning/src/chain/channelmonitor.rs
* lightning/src/events/mod.rs
* lightning/src/ln/channelmanager.rs
* lightning/src/ln/mod.rs
* lightning/src/ln/offers_tests.rs
* lightning/src/ln/onion_utils.rs
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@tnull@ldk-reviews-bot@ldk-claude-review-bot@TheBlueMatt
, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links"); } } catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); } })(); (function(){ try { var __m = "youtube.com"; var __re = new RegExp('^' + "youtube\\.com" + '
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Handle overflowing route-hint fee aggregates - #4716

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TheBlueMatt merged 1 commit into
lightningdevkit:mainfrom
tnull:tnull/2026-05-fix-route-hint-overflow
Jun 18, 2026
Merged

Handle overflowing route-hint fee aggregates#4716
TheBlueMatt merged 1 commit into
lightningdevkit:mainfrom
tnull:tnull/2026-05-fix-route-hint-overflow

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@tnull

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Crafted route hints can overflow aggregate downstream proportional fees when the payer disables the routing fee cap. Treat such paths as unusable so route finding fails cleanly instead of panicking.

Reported by Project Loupe

Crafted route hints can overflow aggregate downstream proportional fees
when the payer disables the routing fee cap. Treat such paths as
unusable so route finding fails cleanly instead of panicking.
Co-Authored-By: HAL 9000
Signed-off-by: Elias Rohrer <dev@tnull.de>
@ldk-reviews-bot

ldk-reviews-bot commented Jun 18, 2026

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I've assigned @wpaulino as a reviewer!
I'll wait for their review and will help manage the review process.
Once they submit their review, I'll check if a second reviewer would be helpful.

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No issues found.

I reviewed the entire diff and traced the supporting code paths:

  • max_final_value_msat now returns Result<(usize, u64), usize>, returning idx + 1 on aggregate-fee overflow. This index is always in bounds, since overflow can only occur when at least one downstream hop exists (compute_aggregated_base_prop_fee returns Ok((0,0)) for an empty iterator), so idx + 1 <= hops.len() - 1.
  • The get_route handler indexes payment_path.hops[candidate_idx_to_skip] safely, logs, marks the candidate exhausted, and continue 'paths_collection. used_liquidities persists across loop iterations, and add_entry saturating-subtracts the u64::MAX value to 0, excluding the candidate — so progress is guaranteed and no infinite loop occurs.
  • mark_candidate_liquidity_exhausted writes both (scid, false)/(scid, true) for clear hops and candidate.id() for the no-scid case, which is consistent with the keys read in max_final_value_msat (hop.candidate.id()) and add_entry ($candidate.id()).
  • The test correctly disables the fee cap (max_total_routing_fee_msat: None) and uses two route-hint hops with proportional_millionths: u32::MAX to trigger the overflow, asserting route.is_err().

Minor (non-blocking) cross-cutting note: the new mark_candidate_liquidity_exhausted helper overlaps with the inline scid-marking block at router.rs:3697-3700 (victim_candidate). Per the repo's DRY guidance that block could call the helper, though doing so would also add the no-scid/blinded else branch, which is a slight behavior change — so leaving it as-is is defensible.

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thanks

match payment_path.max_final_value_msat(&used_liquidities, channel_saturation_pow_half) {
Ok(contribution) => contribution,
Err(candidate_idx_to_skip) => {
let candidate = &payment_path.hops[candidate_idx_to_skip].0.candidate;

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The fact that this can't index OOB is incredibly subtle (compute_aggregated_base_prop_fee won't fail if next_hops_feerates_iter is empty, which will happen if we're at the end). Might be worth clarifying somewhere in a comment.

@TheBlueMatt
TheBlueMatt merged commit 61e3cab into lightningdevkit:mainJun 18, 2026
1 check passed
This was referenced Jun 18, 2026
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Backported to 0.2 in #4722.

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Backported to 0.1 in #4720.

TheBlueMatt added a commit that referenced this pull request Jun 19, 2026
v0.1.10 - Jun 18, 2026 - "Loupe de Loupe"
API Updates
===========
* `DefaultMessageRouter` will now always generate blinded message paths that
provide no privacy (where our node is the introduction node) for nodes with
public channels. This works around an issue which will appear for any nodes
with LND peers that enable onion messaging - such peers will refuse to
forward BOLT 12 messages from unknown third parties, which most BOLT 12
payers rely on today (#4647).
* Explicit `amount_msats` of 0 is rejected in BOLT 12 `Offer`s; `OfferBuilder`
now maps 0-amounts to an amount of `None` (#4324).
Bug Fixes
=========
* Async `ChannelMonitorUpdate` persistence operations which complete, but are
not marked as complete in a persisted `ChannelManager` prior to restart,
followed immediately by a block connection and then another restart could
result in some channel operations hanging leading for force-closures (#4377).
* If an MPP payment is claimed but `ChannelMonitorUpdate`s for some parts are
still being completed asynchronously, further channel updates (e.g.
forwarding another payment) are pending and the node restarts, the channel
could have become stuck (#4520).
* The presence of unconfirmed transactions actually no longer causes
`ElectrumSyncClient` to spuriously fail to sync (#4590).
* `FilesystemStore::list_all_keys` will no longer fail if there are stale
intermediate files lying around from a previous unclean shutdown (#4618).
* When forwarding an HTLC while in a blinded path with proportional fees over
200%, LDK will no longer spuriously allow a forward that pays us 1 msat too
little in fees (#4697).
* Fixed a rare case where a channel could get stuck on reconnect when using
both async `ChannelMonitorUpdate` persistence and async signing (#4684).
* `Event::PaymentSent::fee_paid_msat` is no longer `None` in cases where
`ChannelManager::abandon_payment` was called before the payment ultimately
completes anyway (#4651).
* Syncing a `ChainMonitor` using the `Confirm` trait will no longer write some
full `ChannelMonitor`s to disk several times per block (#4544).
* `OMDomainResolver` now correctly accounts for failed queries when rate
limiting, ensuring we continue to respond to queries after failures (#4591).
* Calling `ChannelManager::send_payment_with_route` without a `route_params`
and with an invalid `Route` will no longer panic (#4707).
* `lightning-custom-message`'s handling of `peer_connected` events now ensures
that sub-handlers will see a `peer_disconnected` event if a different
sub-handler refused the connection by `Err`ing `peer_connected` (#4595).
* Incomplete MPP keysend payments will no longer see their HTLCs held until
expiry (#4558).
* `InvoiceRequestBuilder` will no longer accept a `quantity` of `0` for a
BOLT 12 `Offer`, allowing any quantity up to a bound (#4667).
* `lightning-custom-message` handlers that return `Ok(None)` when asked to
deserialize a message in their defined range no longer cause panics (#4709).
* Several spurious debug assertions were fixed (#4537, #4618).
Security
========
0.1.10 fixes a sanitization issue and several denial-of-service vulnerabilities.
* `Bolt11Invoice::recover_payee_pub_key` no longer panics if called on an
invoice which set an explicit public key, rather than relying on public key
recovery. This method is called from `payment_parameters_from_invoice` and
`payment_parameters_from_variable_amount_invoice` (#4717).
* Maliciously-crafted unpayable invoices which have overflowing feerates will
no longer cause an `unwrap` failure panic (#4716).
* `possiblyrandom` did not properly generate random data except when it was
explicitly configured to. By default this means LDK is vulnerable to various
HashDoS attacks (#4719).
* `OMNameResolver` will no longer panic when looking up payment instructions
which include unicode characters at the start of a TXT record (#4718).
* `PrintableString` did not properly sanitize unicode format characters,
allowing an attacker to corrupt the rendering of logs or UI (#4593, #4605).
* RGS data is now limited in how large of a graph it is able to cause a client
to store in memory. Note that RGS data is still considered a DoS vector in
general and you should only use semi-trusted RGS data (#4713).
* Counterparty-provided strings in failure messages are no longer logged in
full, reducing the ability of such a counterparty to spam our logs (#4714).
* Reading a corrupted `ChannelManager` or `ProbabilisticScorer` can no longer
cause us to allocate large amounts of memory (#4712).
Thanks to Project Loupe for reporting most of the issues fixed in this release.
TheBlueMatt added a commit to TheBlueMatt/rust-lightning that referenced this pull request Jun 23, 2026
v0.2.3 - Jun 18, 2026 - "Through the Loupe"
API Updates
===========
* `DefaultMessageRouter` will now always generate blinded message paths that
provide no privacy (where our node is the introduction node) for nodes with
public channels. This works around an issue which will appear for any nodes
with LND peers that enable onion messaging - such peers will refuse to
forward BOLT 12 messages from unknown third parties, which most BOLT 12
payers rely on today (lightningdevkit#4647).
* Explicit `amount_msats` of 0 is rejected in BOLT 12 `Offer`s; `OfferBuilder`
now maps 0-amounts to an amount of `None` (lightningdevkit#4324).
Bug Fixes
=========
* `Features::supports_zero_conf` no longer clears the `ZeroConf` features and
`Features::requires_zero_conf` now correctly reports required, rather than
supported, status (lightningdevkit#4517).
* If an MPP payment is claimed but `ChannelMonitorUpdate`s for some parts are
still being completed asynchronously, further channel updates (e.g.
forwarding another payment) are pending and the node restarts, the channel
could have become stuck (lightningdevkit#4520).
* The presence of unconfirmed transactions actually no longer causes
`ElectrumSyncClient` to spuriously fail to sync (lightningdevkit#4590).
* LSPS1, LSPS2, and LSPS5 persistence will no longer get stuck and refuse to
persist again after a single failure from the KVStore (lightningdevkit#4597, lightningdevkit#4282).
* Dropping the future returned by
`OutputSweeper::regenerate_and_broadcast_spend_if_necessary` no longer
results in future calls to the same method being spuriously ignored (lightningdevkit#4598).
* Used async-receive offers are no longer refreshed on every timer tick once
their refresh time is reached (lightningdevkit#4672).
* `FilesystemStore::list_all_keys` will no longer fail if there are stale
intermediate files lying around from a previous unclean shutdown (lightningdevkit#4618).
* When forwarding an HTLC while in a blinded path with proportional fees over
200%, LDK will no longer spuriously allow a forward that pays us 1 msat too
little in fees (lightningdevkit#4697).
* Fixed a rare case where a channel could get stuck on reconnect when using
both async `ChannelMonitorUpdate` persistence and async signing (lightningdevkit#4684).
* If we had exactly zero balance in a zero-fee-commitment channel, the
counterparty was able to splice all of their balance out, violating the
reserve requirements they'd otherwise be forced to keep (lightningdevkit#4580).
* Providing an `Event::HTLCIntercepted` to the `LSPS2ServiceHandler` twice no
longer results in spuriously opening a channel early (lightningdevkit#4656).
* `Event::PaymentSent::fee_paid_msat` is no longer `None` in cases where
`ChannelManager::abandon_payment` was called before the payment ultimately
completes anyway (lightningdevkit#4651).
* `AnchorDescriptor::previous_utxo` now provides the correct `script_pubkey`
for non-zero-commitment-fee anchor channels (lightningdevkit#4669).
* Syncing a `ChainMonitor` using the `Confirm` trait will no longer write some
full `ChannelMonitor`s to disk several times per block (lightningdevkit#4544).
* `OMDomainResolver` now correctly accounts for failed queries when rate
limiting, ensuring we continue to respond to queries after failures (lightningdevkit#4591).
* Calling `ChannelManager::send_payment_with_route` without a `route_params`
and with an invalid `Route` will no longer panic (lightningdevkit#4707).
* `LSPS2ServiceHandler::channel_open_failed` now correctly fails intercepted
HTLCs rather than allowing them to fail just before expiry (lightningdevkit#4677).
* `StaticInvoice::is_offer_expired` was corrected to check offer, rather than
static invoice, expiry (lightningdevkit#4594).
* `lightning-custom-message`'s handling of `peer_connected` events now ensures
that sub-handlers will see a `peer_disconnected` event if a different
sub-handler refused the connection by `Err`ing `peer_connected` (lightningdevkit#4595).
* Replay protection for LSPS5 signatures now detects replays which are only
different in the encoded signature's case (lightningdevkit#4701).
* When `lightning-liquidity` is configured in the background processor, there
is no longer a stream of `Persisting LiquidityManager...` log spam (lightningdevkit#4246).
* Incomplete MPP keysend payments will no longer see their HTLCs held until
expiry (lightningdevkit#4558).
* `InvoiceRequestBuilder` will no longer accept a `quantity` of `0` for a
BOLT 12 `Offer`, allowing any quantity up to a bound (lightningdevkit#4667).
* `lightning-custom-message` handlers that return `Ok(None)` when asked to
deserialize a message in their defined range no longer cause panics (lightningdevkit#4709).
* Several spurious debug assertions were fixed (lightningdevkit#4537, lightningdevkit#4618, lightningdevkit#4026)
Security
========
0.2.3 fixes several underestimates of the anchor reserves required to ensure we
can reliably close channels, several denial-of-service vulnerabilities and a
sanitization issue.
* `Bolt11Invoice::recover_payee_pub_key` no longer panics if called on an
invoice which set an explicit public key, rather than relying on public key
recovery. Note that this method is called from
`PaymentParameters::from_bolt11_invoice` (lightningdevkit#4717).
* Maliciously-crafted unpayable invoices which have overflowing feerates will
no longer cause an `unwrap` failure panic (lightningdevkit#4716).
* Parsing an `LSPSDateTime` which is before 1970 no longer panics. This is
reachable when parsing messages from counterparties (lightningdevkit#4715).
* `possiblyrandom` did not properly generate random data except when it was
explicitly configured to. By default this means LDK is vulnerable to various
HashDoS attacks (lightningdevkit#4719).
* `OMNameResolver` will no longer panic when looking up payment instructions
which include unicode characters at the start of a TXT record (lightningdevkit#4718).
* When using the `anchor_channel_reserves` module to calculate reserves
required to pay for fees when closing anchor channels, zero-fee-commitment
channels were not considered. This could allow a counterparty to open many
channels, leaving us unable to properly force-close (lightningdevkit#4592).
* The `anchor_channel_reserves` module overestimated the value of `Utxo`s in
the wallet by ignoring the `TxIn` cost to spend them (lightningdevkit#4670).
* `PrintableString` did not properly sanitize unicode format characters,
allowing an attacker to corrupt the rendering of logs or UI (lightningdevkit#4593, lightningdevkit#4605).
* RGS data is now limited in how large of a graph it is able to cause a client
to store in memory. Note that RGS data is still considered a DoS vector in
general and you should only use semi-trusted RGS data (lightningdevkit#4713).
* Counterparty-provided strings in failure messages are no longer logged in
full, reducing the ability of such a counterparty to spam our logs (lightningdevkit#4714).
* Reading a corrupted `ChannelManager` or `ProbabilisticScorer` can no longer
cause us to allocate large amounts of memory (lightningdevkit#4712).
Thanks to Project Loupe for reporting most of the issues fixed in this release.
Conflicts resolved in:
* lightning/src/chain/channelmonitor.rs
* lightning/src/events/mod.rs
* lightning/src/ln/channelmanager.rs
* lightning/src/ln/mod.rs
* lightning/src/ln/offers_tests.rs
* lightning/src/ln/onion_utils.rs
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, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default"); } } catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); } })(); (function(){ try { var __m = "*"; var __re = new RegExp('^' + ".*" + '
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Handle overflowing route-hint fee aggregates - #4716

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TheBlueMatt merged 1 commit into
lightningdevkit:mainfrom
tnull:tnull/2026-05-fix-route-hint-overflow
Jun 18, 2026
Merged

Handle overflowing route-hint fee aggregates#4716
TheBlueMatt merged 1 commit into
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tnull:tnull/2026-05-fix-route-hint-overflow

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Crafted route hints can overflow aggregate downstream proportional fees when the payer disables the routing fee cap. Treat such paths as unusable so route finding fails cleanly instead of panicking.

Reported by Project Loupe

Crafted route hints can overflow aggregate downstream proportional fees
when the payer disables the routing fee cap. Treat such paths as
unusable so route finding fails cleanly instead of panicking.
Co-Authored-By: HAL 9000
Signed-off-by: Elias Rohrer <dev@tnull.de>
@ldk-reviews-bot

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I've assigned @wpaulino as a reviewer!
I'll wait for their review and will help manage the review process.
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No issues found.

I reviewed the entire diff and traced the supporting code paths:

  • max_final_value_msat now returns Result<(usize, u64), usize>, returning idx + 1 on aggregate-fee overflow. This index is always in bounds, since overflow can only occur when at least one downstream hop exists (compute_aggregated_base_prop_fee returns Ok((0,0)) for an empty iterator), so idx + 1 <= hops.len() - 1.
  • The get_route handler indexes payment_path.hops[candidate_idx_to_skip] safely, logs, marks the candidate exhausted, and continue 'paths_collection. used_liquidities persists across loop iterations, and add_entry saturating-subtracts the u64::MAX value to 0, excluding the candidate — so progress is guaranteed and no infinite loop occurs.
  • mark_candidate_liquidity_exhausted writes both (scid, false)/(scid, true) for clear hops and candidate.id() for the no-scid case, which is consistent with the keys read in max_final_value_msat (hop.candidate.id()) and add_entry ($candidate.id()).
  • The test correctly disables the fee cap (max_total_routing_fee_msat: None) and uses two route-hint hops with proportional_millionths: u32::MAX to trigger the overflow, asserting route.is_err().

Minor (non-blocking) cross-cutting note: the new mark_candidate_liquidity_exhausted helper overlaps with the inline scid-marking block at router.rs:3697-3700 (victim_candidate). Per the repo's DRY guidance that block could call the helper, though doing so would also add the no-scid/blinded else branch, which is a slight behavior change — so leaving it as-is is defensible.

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thanks

match payment_path.max_final_value_msat(&used_liquidities, channel_saturation_pow_half) {
Ok(contribution) => contribution,
Err(candidate_idx_to_skip) => {
let candidate = &payment_path.hops[candidate_idx_to_skip].0.candidate;

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The fact that this can't index OOB is incredibly subtle (compute_aggregated_base_prop_fee won't fail if next_hops_feerates_iter is empty, which will happen if we're at the end). Might be worth clarifying somewhere in a comment.

@TheBlueMatt
TheBlueMatt merged commit 61e3cab into lightningdevkit:mainJun 18, 2026
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This was referenced Jun 18, 2026
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Backported to 0.2 in #4722.

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Backported to 0.1 in #4720.

TheBlueMatt added a commit that referenced this pull request Jun 19, 2026
v0.1.10 - Jun 18, 2026 - "Loupe de Loupe"
API Updates
===========
* `DefaultMessageRouter` will now always generate blinded message paths that
provide no privacy (where our node is the introduction node) for nodes with
public channels. This works around an issue which will appear for any nodes
with LND peers that enable onion messaging - such peers will refuse to
forward BOLT 12 messages from unknown third parties, which most BOLT 12
payers rely on today (#4647).
* Explicit `amount_msats` of 0 is rejected in BOLT 12 `Offer`s; `OfferBuilder`
now maps 0-amounts to an amount of `None` (#4324).
Bug Fixes
=========
* Async `ChannelMonitorUpdate` persistence operations which complete, but are
not marked as complete in a persisted `ChannelManager` prior to restart,
followed immediately by a block connection and then another restart could
result in some channel operations hanging leading for force-closures (#4377).
* If an MPP payment is claimed but `ChannelMonitorUpdate`s for some parts are
still being completed asynchronously, further channel updates (e.g.
forwarding another payment) are pending and the node restarts, the channel
could have become stuck (#4520).
* The presence of unconfirmed transactions actually no longer causes
`ElectrumSyncClient` to spuriously fail to sync (#4590).
* `FilesystemStore::list_all_keys` will no longer fail if there are stale
intermediate files lying around from a previous unclean shutdown (#4618).
* When forwarding an HTLC while in a blinded path with proportional fees over
200%, LDK will no longer spuriously allow a forward that pays us 1 msat too
little in fees (#4697).
* Fixed a rare case where a channel could get stuck on reconnect when using
both async `ChannelMonitorUpdate` persistence and async signing (#4684).
* `Event::PaymentSent::fee_paid_msat` is no longer `None` in cases where
`ChannelManager::abandon_payment` was called before the payment ultimately
completes anyway (#4651).
* Syncing a `ChainMonitor` using the `Confirm` trait will no longer write some
full `ChannelMonitor`s to disk several times per block (#4544).
* `OMDomainResolver` now correctly accounts for failed queries when rate
limiting, ensuring we continue to respond to queries after failures (#4591).
* Calling `ChannelManager::send_payment_with_route` without a `route_params`
and with an invalid `Route` will no longer panic (#4707).
* `lightning-custom-message`'s handling of `peer_connected` events now ensures
that sub-handlers will see a `peer_disconnected` event if a different
sub-handler refused the connection by `Err`ing `peer_connected` (#4595).
* Incomplete MPP keysend payments will no longer see their HTLCs held until
expiry (#4558).
* `InvoiceRequestBuilder` will no longer accept a `quantity` of `0` for a
BOLT 12 `Offer`, allowing any quantity up to a bound (#4667).
* `lightning-custom-message` handlers that return `Ok(None)` when asked to
deserialize a message in their defined range no longer cause panics (#4709).
* Several spurious debug assertions were fixed (#4537, #4618).
Security
========
0.1.10 fixes a sanitization issue and several denial-of-service vulnerabilities.
* `Bolt11Invoice::recover_payee_pub_key` no longer panics if called on an
invoice which set an explicit public key, rather than relying on public key
recovery. This method is called from `payment_parameters_from_invoice` and
`payment_parameters_from_variable_amount_invoice` (#4717).
* Maliciously-crafted unpayable invoices which have overflowing feerates will
no longer cause an `unwrap` failure panic (#4716).
* `possiblyrandom` did not properly generate random data except when it was
explicitly configured to. By default this means LDK is vulnerable to various
HashDoS attacks (#4719).
* `OMNameResolver` will no longer panic when looking up payment instructions
which include unicode characters at the start of a TXT record (#4718).
* `PrintableString` did not properly sanitize unicode format characters,
allowing an attacker to corrupt the rendering of logs or UI (#4593, #4605).
* RGS data is now limited in how large of a graph it is able to cause a client
to store in memory. Note that RGS data is still considered a DoS vector in
general and you should only use semi-trusted RGS data (#4713).
* Counterparty-provided strings in failure messages are no longer logged in
full, reducing the ability of such a counterparty to spam our logs (#4714).
* Reading a corrupted `ChannelManager` or `ProbabilisticScorer` can no longer
cause us to allocate large amounts of memory (#4712).
Thanks to Project Loupe for reporting most of the issues fixed in this release.
TheBlueMatt added a commit to TheBlueMatt/rust-lightning that referenced this pull request Jun 23, 2026
v0.2.3 - Jun 18, 2026 - "Through the Loupe"
API Updates
===========
* `DefaultMessageRouter` will now always generate blinded message paths that
provide no privacy (where our node is the introduction node) for nodes with
public channels. This works around an issue which will appear for any nodes
with LND peers that enable onion messaging - such peers will refuse to
forward BOLT 12 messages from unknown third parties, which most BOLT 12
payers rely on today (lightningdevkit#4647).
* Explicit `amount_msats` of 0 is rejected in BOLT 12 `Offer`s; `OfferBuilder`
now maps 0-amounts to an amount of `None` (lightningdevkit#4324).
Bug Fixes
=========
* `Features::supports_zero_conf` no longer clears the `ZeroConf` features and
`Features::requires_zero_conf` now correctly reports required, rather than
supported, status (lightningdevkit#4517).
* If an MPP payment is claimed but `ChannelMonitorUpdate`s for some parts are
still being completed asynchronously, further channel updates (e.g.
forwarding another payment) are pending and the node restarts, the channel
could have become stuck (lightningdevkit#4520).
* The presence of unconfirmed transactions actually no longer causes
`ElectrumSyncClient` to spuriously fail to sync (lightningdevkit#4590).
* LSPS1, LSPS2, and LSPS5 persistence will no longer get stuck and refuse to
persist again after a single failure from the KVStore (lightningdevkit#4597, lightningdevkit#4282).
* Dropping the future returned by
`OutputSweeper::regenerate_and_broadcast_spend_if_necessary` no longer
results in future calls to the same method being spuriously ignored (lightningdevkit#4598).
* Used async-receive offers are no longer refreshed on every timer tick once
their refresh time is reached (lightningdevkit#4672).
* `FilesystemStore::list_all_keys` will no longer fail if there are stale
intermediate files lying around from a previous unclean shutdown (lightningdevkit#4618).
* When forwarding an HTLC while in a blinded path with proportional fees over
200%, LDK will no longer spuriously allow a forward that pays us 1 msat too
little in fees (lightningdevkit#4697).
* Fixed a rare case where a channel could get stuck on reconnect when using
both async `ChannelMonitorUpdate` persistence and async signing (lightningdevkit#4684).
* If we had exactly zero balance in a zero-fee-commitment channel, the
counterparty was able to splice all of their balance out, violating the
reserve requirements they'd otherwise be forced to keep (lightningdevkit#4580).
* Providing an `Event::HTLCIntercepted` to the `LSPS2ServiceHandler` twice no
longer results in spuriously opening a channel early (lightningdevkit#4656).
* `Event::PaymentSent::fee_paid_msat` is no longer `None` in cases where
`ChannelManager::abandon_payment` was called before the payment ultimately
completes anyway (lightningdevkit#4651).
* `AnchorDescriptor::previous_utxo` now provides the correct `script_pubkey`
for non-zero-commitment-fee anchor channels (lightningdevkit#4669).
* Syncing a `ChainMonitor` using the `Confirm` trait will no longer write some
full `ChannelMonitor`s to disk several times per block (lightningdevkit#4544).
* `OMDomainResolver` now correctly accounts for failed queries when rate
limiting, ensuring we continue to respond to queries after failures (lightningdevkit#4591).
* Calling `ChannelManager::send_payment_with_route` without a `route_params`
and with an invalid `Route` will no longer panic (lightningdevkit#4707).
* `LSPS2ServiceHandler::channel_open_failed` now correctly fails intercepted
HTLCs rather than allowing them to fail just before expiry (lightningdevkit#4677).
* `StaticInvoice::is_offer_expired` was corrected to check offer, rather than
static invoice, expiry (lightningdevkit#4594).
* `lightning-custom-message`'s handling of `peer_connected` events now ensures
that sub-handlers will see a `peer_disconnected` event if a different
sub-handler refused the connection by `Err`ing `peer_connected` (lightningdevkit#4595).
* Replay protection for LSPS5 signatures now detects replays which are only
different in the encoded signature's case (lightningdevkit#4701).
* When `lightning-liquidity` is configured in the background processor, there
is no longer a stream of `Persisting LiquidityManager...` log spam (lightningdevkit#4246).
* Incomplete MPP keysend payments will no longer see their HTLCs held until
expiry (lightningdevkit#4558).
* `InvoiceRequestBuilder` will no longer accept a `quantity` of `0` for a
BOLT 12 `Offer`, allowing any quantity up to a bound (lightningdevkit#4667).
* `lightning-custom-message` handlers that return `Ok(None)` when asked to
deserialize a message in their defined range no longer cause panics (lightningdevkit#4709).
* Several spurious debug assertions were fixed (lightningdevkit#4537, lightningdevkit#4618, lightningdevkit#4026)
Security
========
0.2.3 fixes several underestimates of the anchor reserves required to ensure we
can reliably close channels, several denial-of-service vulnerabilities and a
sanitization issue.
* `Bolt11Invoice::recover_payee_pub_key` no longer panics if called on an
invoice which set an explicit public key, rather than relying on public key
recovery. Note that this method is called from
`PaymentParameters::from_bolt11_invoice` (lightningdevkit#4717).
* Maliciously-crafted unpayable invoices which have overflowing feerates will
no longer cause an `unwrap` failure panic (lightningdevkit#4716).
* Parsing an `LSPSDateTime` which is before 1970 no longer panics. This is
reachable when parsing messages from counterparties (lightningdevkit#4715).
* `possiblyrandom` did not properly generate random data except when it was
explicitly configured to. By default this means LDK is vulnerable to various
HashDoS attacks (lightningdevkit#4719).
* `OMNameResolver` will no longer panic when looking up payment instructions
which include unicode characters at the start of a TXT record (lightningdevkit#4718).
* When using the `anchor_channel_reserves` module to calculate reserves
required to pay for fees when closing anchor channels, zero-fee-commitment
channels were not considered. This could allow a counterparty to open many
channels, leaving us unable to properly force-close (lightningdevkit#4592).
* The `anchor_channel_reserves` module overestimated the value of `Utxo`s in
the wallet by ignoring the `TxIn` cost to spend them (lightningdevkit#4670).
* `PrintableString` did not properly sanitize unicode format characters,
allowing an attacker to corrupt the rendering of logs or UI (lightningdevkit#4593, lightningdevkit#4605).
* RGS data is now limited in how large of a graph it is able to cause a client
to store in memory. Note that RGS data is still considered a DoS vector in
general and you should only use semi-trusted RGS data (lightningdevkit#4713).
* Counterparty-provided strings in failure messages are no longer logged in
full, reducing the ability of such a counterparty to spam our logs (lightningdevkit#4714).
* Reading a corrupted `ChannelManager` or `ProbabilisticScorer` can no longer
cause us to allocate large amounts of memory (lightningdevkit#4712).
Thanks to Project Loupe for reporting most of the issues fixed in this release.
Conflicts resolved in:
* lightning/src/chain/channelmonitor.rs
* lightning/src/events/mod.rs
* lightning/src/ln/channelmanager.rs
* lightning/src/ln/mod.rs
* lightning/src/ln/offers_tests.rs
* lightning/src/ln/onion_utils.rs
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, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers"); } } catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); } })(); (function(){ try { var __m = "*"; var __re = new RegExp('^' + ".*" + '
Skip to content

Handle overflowing route-hint fee aggregates - #4716

Merged
TheBlueMatt merged 1 commit into
lightningdevkit:mainfrom
tnull:tnull/2026-05-fix-route-hint-overflow
Jun 18, 2026
Merged

Handle overflowing route-hint fee aggregates#4716
TheBlueMatt merged 1 commit into
lightningdevkit:mainfrom
tnull:tnull/2026-05-fix-route-hint-overflow

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@tnull

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Crafted route hints can overflow aggregate downstream proportional fees when the payer disables the routing fee cap. Treat such paths as unusable so route finding fails cleanly instead of panicking.

Reported by Project Loupe

Crafted route hints can overflow aggregate downstream proportional fees
when the payer disables the routing fee cap. Treat such paths as
unusable so route finding fails cleanly instead of panicking.
Co-Authored-By: HAL 9000
Signed-off-by: Elias Rohrer <dev@tnull.de>
@ldk-reviews-bot

ldk-reviews-bot commented Jun 18, 2026

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I've assigned @wpaulino as a reviewer!
I'll wait for their review and will help manage the review process.
Once they submit their review, I'll check if a second reviewer would be helpful.

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No issues found.

I reviewed the entire diff and traced the supporting code paths:

  • max_final_value_msat now returns Result<(usize, u64), usize>, returning idx + 1 on aggregate-fee overflow. This index is always in bounds, since overflow can only occur when at least one downstream hop exists (compute_aggregated_base_prop_fee returns Ok((0,0)) for an empty iterator), so idx + 1 <= hops.len() - 1.
  • The get_route handler indexes payment_path.hops[candidate_idx_to_skip] safely, logs, marks the candidate exhausted, and continue 'paths_collection. used_liquidities persists across loop iterations, and add_entry saturating-subtracts the u64::MAX value to 0, excluding the candidate — so progress is guaranteed and no infinite loop occurs.
  • mark_candidate_liquidity_exhausted writes both (scid, false)/(scid, true) for clear hops and candidate.id() for the no-scid case, which is consistent with the keys read in max_final_value_msat (hop.candidate.id()) and add_entry ($candidate.id()).
  • The test correctly disables the fee cap (max_total_routing_fee_msat: None) and uses two route-hint hops with proportional_millionths: u32::MAX to trigger the overflow, asserting route.is_err().

Minor (non-blocking) cross-cutting note: the new mark_candidate_liquidity_exhausted helper overlaps with the inline scid-marking block at router.rs:3697-3700 (victim_candidate). Per the repo's DRY guidance that block could call the helper, though doing so would also add the no-scid/blinded else branch, which is a slight behavior change — so leaving it as-is is defensible.

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thanks

match payment_path.max_final_value_msat(&used_liquidities, channel_saturation_pow_half) {
Ok(contribution) => contribution,
Err(candidate_idx_to_skip) => {
let candidate = &payment_path.hops[candidate_idx_to_skip].0.candidate;

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The fact that this can't index OOB is incredibly subtle (compute_aggregated_base_prop_fee won't fail if next_hops_feerates_iter is empty, which will happen if we're at the end). Might be worth clarifying somewhere in a comment.

@TheBlueMatt
TheBlueMatt merged commit 61e3cab into lightningdevkit:mainJun 18, 2026
1 check passed
This was referenced Jun 18, 2026
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Backported to 0.2 in #4722.

@TheBlueMatt

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Backported to 0.1 in #4720.

TheBlueMatt added a commit that referenced this pull request Jun 19, 2026
v0.1.10 - Jun 18, 2026 - "Loupe de Loupe"
API Updates
===========
* `DefaultMessageRouter` will now always generate blinded message paths that
provide no privacy (where our node is the introduction node) for nodes with
public channels. This works around an issue which will appear for any nodes
with LND peers that enable onion messaging - such peers will refuse to
forward BOLT 12 messages from unknown third parties, which most BOLT 12
payers rely on today (#4647).
* Explicit `amount_msats` of 0 is rejected in BOLT 12 `Offer`s; `OfferBuilder`
now maps 0-amounts to an amount of `None` (#4324).
Bug Fixes
=========
* Async `ChannelMonitorUpdate` persistence operations which complete, but are
not marked as complete in a persisted `ChannelManager` prior to restart,
followed immediately by a block connection and then another restart could
result in some channel operations hanging leading for force-closures (#4377).
* If an MPP payment is claimed but `ChannelMonitorUpdate`s for some parts are
still being completed asynchronously, further channel updates (e.g.
forwarding another payment) are pending and the node restarts, the channel
could have become stuck (#4520).
* The presence of unconfirmed transactions actually no longer causes
`ElectrumSyncClient` to spuriously fail to sync (#4590).
* `FilesystemStore::list_all_keys` will no longer fail if there are stale
intermediate files lying around from a previous unclean shutdown (#4618).
* When forwarding an HTLC while in a blinded path with proportional fees over
200%, LDK will no longer spuriously allow a forward that pays us 1 msat too
little in fees (#4697).
* Fixed a rare case where a channel could get stuck on reconnect when using
both async `ChannelMonitorUpdate` persistence and async signing (#4684).
* `Event::PaymentSent::fee_paid_msat` is no longer `None` in cases where
`ChannelManager::abandon_payment` was called before the payment ultimately
completes anyway (#4651).
* Syncing a `ChainMonitor` using the `Confirm` trait will no longer write some
full `ChannelMonitor`s to disk several times per block (#4544).
* `OMDomainResolver` now correctly accounts for failed queries when rate
limiting, ensuring we continue to respond to queries after failures (#4591).
* Calling `ChannelManager::send_payment_with_route` without a `route_params`
and with an invalid `Route` will no longer panic (#4707).
* `lightning-custom-message`'s handling of `peer_connected` events now ensures
that sub-handlers will see a `peer_disconnected` event if a different
sub-handler refused the connection by `Err`ing `peer_connected` (#4595).
* Incomplete MPP keysend payments will no longer see their HTLCs held until
expiry (#4558).
* `InvoiceRequestBuilder` will no longer accept a `quantity` of `0` for a
BOLT 12 `Offer`, allowing any quantity up to a bound (#4667).
* `lightning-custom-message` handlers that return `Ok(None)` when asked to
deserialize a message in their defined range no longer cause panics (#4709).
* Several spurious debug assertions were fixed (#4537, #4618).
Security
========
0.1.10 fixes a sanitization issue and several denial-of-service vulnerabilities.
* `Bolt11Invoice::recover_payee_pub_key` no longer panics if called on an
invoice which set an explicit public key, rather than relying on public key
recovery. This method is called from `payment_parameters_from_invoice` and
`payment_parameters_from_variable_amount_invoice` (#4717).
* Maliciously-crafted unpayable invoices which have overflowing feerates will
no longer cause an `unwrap` failure panic (#4716).
* `possiblyrandom` did not properly generate random data except when it was
explicitly configured to. By default this means LDK is vulnerable to various
HashDoS attacks (#4719).
* `OMNameResolver` will no longer panic when looking up payment instructions
which include unicode characters at the start of a TXT record (#4718).
* `PrintableString` did not properly sanitize unicode format characters,
allowing an attacker to corrupt the rendering of logs or UI (#4593, #4605).
* RGS data is now limited in how large of a graph it is able to cause a client
to store in memory. Note that RGS data is still considered a DoS vector in
general and you should only use semi-trusted RGS data (#4713).
* Counterparty-provided strings in failure messages are no longer logged in
full, reducing the ability of such a counterparty to spam our logs (#4714).
* Reading a corrupted `ChannelManager` or `ProbabilisticScorer` can no longer
cause us to allocate large amounts of memory (#4712).
Thanks to Project Loupe for reporting most of the issues fixed in this release.
TheBlueMatt added a commit to TheBlueMatt/rust-lightning that referenced this pull request Jun 23, 2026
v0.2.3 - Jun 18, 2026 - "Through the Loupe"
API Updates
===========
* `DefaultMessageRouter` will now always generate blinded message paths that
provide no privacy (where our node is the introduction node) for nodes with
public channels. This works around an issue which will appear for any nodes
with LND peers that enable onion messaging - such peers will refuse to
forward BOLT 12 messages from unknown third parties, which most BOLT 12
payers rely on today (lightningdevkit#4647).
* Explicit `amount_msats` of 0 is rejected in BOLT 12 `Offer`s; `OfferBuilder`
now maps 0-amounts to an amount of `None` (lightningdevkit#4324).
Bug Fixes
=========
* `Features::supports_zero_conf` no longer clears the `ZeroConf` features and
`Features::requires_zero_conf` now correctly reports required, rather than
supported, status (lightningdevkit#4517).
* If an MPP payment is claimed but `ChannelMonitorUpdate`s for some parts are
still being completed asynchronously, further channel updates (e.g.
forwarding another payment) are pending and the node restarts, the channel
could have become stuck (lightningdevkit#4520).
* The presence of unconfirmed transactions actually no longer causes
`ElectrumSyncClient` to spuriously fail to sync (lightningdevkit#4590).
* LSPS1, LSPS2, and LSPS5 persistence will no longer get stuck and refuse to
persist again after a single failure from the KVStore (lightningdevkit#4597, lightningdevkit#4282).
* Dropping the future returned by
`OutputSweeper::regenerate_and_broadcast_spend_if_necessary` no longer
results in future calls to the same method being spuriously ignored (lightningdevkit#4598).
* Used async-receive offers are no longer refreshed on every timer tick once
their refresh time is reached (lightningdevkit#4672).
* `FilesystemStore::list_all_keys` will no longer fail if there are stale
intermediate files lying around from a previous unclean shutdown (lightningdevkit#4618).
* When forwarding an HTLC while in a blinded path with proportional fees over
200%, LDK will no longer spuriously allow a forward that pays us 1 msat too
little in fees (lightningdevkit#4697).
* Fixed a rare case where a channel could get stuck on reconnect when using
both async `ChannelMonitorUpdate` persistence and async signing (lightningdevkit#4684).
* If we had exactly zero balance in a zero-fee-commitment channel, the
counterparty was able to splice all of their balance out, violating the
reserve requirements they'd otherwise be forced to keep (lightningdevkit#4580).
* Providing an `Event::HTLCIntercepted` to the `LSPS2ServiceHandler` twice no
longer results in spuriously opening a channel early (lightningdevkit#4656).
* `Event::PaymentSent::fee_paid_msat` is no longer `None` in cases where
`ChannelManager::abandon_payment` was called before the payment ultimately
completes anyway (lightningdevkit#4651).
* `AnchorDescriptor::previous_utxo` now provides the correct `script_pubkey`
for non-zero-commitment-fee anchor channels (lightningdevkit#4669).
* Syncing a `ChainMonitor` using the `Confirm` trait will no longer write some
full `ChannelMonitor`s to disk several times per block (lightningdevkit#4544).
* `OMDomainResolver` now correctly accounts for failed queries when rate
limiting, ensuring we continue to respond to queries after failures (lightningdevkit#4591).
* Calling `ChannelManager::send_payment_with_route` without a `route_params`
and with an invalid `Route` will no longer panic (lightningdevkit#4707).
* `LSPS2ServiceHandler::channel_open_failed` now correctly fails intercepted
HTLCs rather than allowing them to fail just before expiry (lightningdevkit#4677).
* `StaticInvoice::is_offer_expired` was corrected to check offer, rather than
static invoice, expiry (lightningdevkit#4594).
* `lightning-custom-message`'s handling of `peer_connected` events now ensures
that sub-handlers will see a `peer_disconnected` event if a different
sub-handler refused the connection by `Err`ing `peer_connected` (lightningdevkit#4595).
* Replay protection for LSPS5 signatures now detects replays which are only
different in the encoded signature's case (lightningdevkit#4701).
* When `lightning-liquidity` is configured in the background processor, there
is no longer a stream of `Persisting LiquidityManager...` log spam (lightningdevkit#4246).
* Incomplete MPP keysend payments will no longer see their HTLCs held until
expiry (lightningdevkit#4558).
* `InvoiceRequestBuilder` will no longer accept a `quantity` of `0` for a
BOLT 12 `Offer`, allowing any quantity up to a bound (lightningdevkit#4667).
* `lightning-custom-message` handlers that return `Ok(None)` when asked to
deserialize a message in their defined range no longer cause panics (lightningdevkit#4709).
* Several spurious debug assertions were fixed (lightningdevkit#4537, lightningdevkit#4618, lightningdevkit#4026)
Security
========
0.2.3 fixes several underestimates of the anchor reserves required to ensure we
can reliably close channels, several denial-of-service vulnerabilities and a
sanitization issue.
* `Bolt11Invoice::recover_payee_pub_key` no longer panics if called on an
invoice which set an explicit public key, rather than relying on public key
recovery. Note that this method is called from
`PaymentParameters::from_bolt11_invoice` (lightningdevkit#4717).
* Maliciously-crafted unpayable invoices which have overflowing feerates will
no longer cause an `unwrap` failure panic (lightningdevkit#4716).
* Parsing an `LSPSDateTime` which is before 1970 no longer panics. This is
reachable when parsing messages from counterparties (lightningdevkit#4715).
* `possiblyrandom` did not properly generate random data except when it was
explicitly configured to. By default this means LDK is vulnerable to various
HashDoS attacks (lightningdevkit#4719).
* `OMNameResolver` will no longer panic when looking up payment instructions
which include unicode characters at the start of a TXT record (lightningdevkit#4718).
* When using the `anchor_channel_reserves` module to calculate reserves
required to pay for fees when closing anchor channels, zero-fee-commitment
channels were not considered. This could allow a counterparty to open many
channels, leaving us unable to properly force-close (lightningdevkit#4592).
* The `anchor_channel_reserves` module overestimated the value of `Utxo`s in
the wallet by ignoring the `TxIn` cost to spend them (lightningdevkit#4670).
* `PrintableString` did not properly sanitize unicode format characters,
allowing an attacker to corrupt the rendering of logs or UI (lightningdevkit#4593, lightningdevkit#4605).
* RGS data is now limited in how large of a graph it is able to cause a client
to store in memory. Note that RGS data is still considered a DoS vector in
general and you should only use semi-trusted RGS data (lightningdevkit#4713).
* Counterparty-provided strings in failure messages are no longer logged in
full, reducing the ability of such a counterparty to spam our logs (lightningdevkit#4714).
* Reading a corrupted `ChannelManager` or `ProbabilisticScorer` can no longer
cause us to allocate large amounts of memory (lightningdevkit#4712).
Thanks to Project Loupe for reporting most of the issues fixed in this release.
Conflicts resolved in:
* lightning/src/chain/channelmonitor.rs
* lightning/src/events/mod.rs
* lightning/src/ln/channelmanager.rs
* lightning/src/ln/mod.rs
* lightning/src/ln/offers_tests.rs
* lightning/src/ln/onion_utils.rs
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, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode"); } } catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); } })(); })();
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Handle overflowing route-hint fee aggregates - #4716

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lightningdevkit:mainfrom
tnull:tnull/2026-05-fix-route-hint-overflow
Jun 18, 2026
Merged

Handle overflowing route-hint fee aggregates#4716
TheBlueMatt merged 1 commit into
lightningdevkit:mainfrom
tnull:tnull/2026-05-fix-route-hint-overflow

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Crafted route hints can overflow aggregate downstream proportional fees when the payer disables the routing fee cap. Treat such paths as unusable so route finding fails cleanly instead of panicking.

Reported by Project Loupe

Crafted route hints can overflow aggregate downstream proportional fees
when the payer disables the routing fee cap. Treat such paths as
unusable so route finding fails cleanly instead of panicking.
Co-Authored-By: HAL 9000
Signed-off-by: Elias Rohrer <dev@tnull.de>
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ldk-reviews-bot commented Jun 18, 2026

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I've assigned @wpaulino as a reviewer!
I'll wait for their review and will help manage the review process.
Once they submit their review, I'll check if a second reviewer would be helpful.

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No issues found.

I reviewed the entire diff and traced the supporting code paths:

  • max_final_value_msat now returns Result<(usize, u64), usize>, returning idx + 1 on aggregate-fee overflow. This index is always in bounds, since overflow can only occur when at least one downstream hop exists (compute_aggregated_base_prop_fee returns Ok((0,0)) for an empty iterator), so idx + 1 <= hops.len() - 1.
  • The get_route handler indexes payment_path.hops[candidate_idx_to_skip] safely, logs, marks the candidate exhausted, and continue 'paths_collection. used_liquidities persists across loop iterations, and add_entry saturating-subtracts the u64::MAX value to 0, excluding the candidate — so progress is guaranteed and no infinite loop occurs.
  • mark_candidate_liquidity_exhausted writes both (scid, false)/(scid, true) for clear hops and candidate.id() for the no-scid case, which is consistent with the keys read in max_final_value_msat (hop.candidate.id()) and add_entry ($candidate.id()).
  • The test correctly disables the fee cap (max_total_routing_fee_msat: None) and uses two route-hint hops with proportional_millionths: u32::MAX to trigger the overflow, asserting route.is_err().

Minor (non-blocking) cross-cutting note: the new mark_candidate_liquidity_exhausted helper overlaps with the inline scid-marking block at router.rs:3697-3700 (victim_candidate). Per the repo's DRY guidance that block could call the helper, though doing so would also add the no-scid/blinded else branch, which is a slight behavior change — so leaving it as-is is defensible.

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thanks

match payment_path.max_final_value_msat(&used_liquidities, channel_saturation_pow_half) {
Ok(contribution) => contribution,
Err(candidate_idx_to_skip) => {
let candidate = &payment_path.hops[candidate_idx_to_skip].0.candidate;

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The fact that this can't index OOB is incredibly subtle (compute_aggregated_base_prop_fee won't fail if next_hops_feerates_iter is empty, which will happen if we're at the end). Might be worth clarifying somewhere in a comment.

@TheBlueMatt
TheBlueMatt merged commit 61e3cab into lightningdevkit:mainJun 18, 2026
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This was referenced Jun 18, 2026
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Backported to 0.2 in #4722.

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Backported to 0.1 in #4720.

TheBlueMatt added a commit that referenced this pull request Jun 19, 2026
v0.1.10 - Jun 18, 2026 - "Loupe de Loupe"
API Updates
===========
* `DefaultMessageRouter` will now always generate blinded message paths that
provide no privacy (where our node is the introduction node) for nodes with
public channels. This works around an issue which will appear for any nodes
with LND peers that enable onion messaging - such peers will refuse to
forward BOLT 12 messages from unknown third parties, which most BOLT 12
payers rely on today (#4647).
* Explicit `amount_msats` of 0 is rejected in BOLT 12 `Offer`s; `OfferBuilder`
now maps 0-amounts to an amount of `None` (#4324).
Bug Fixes
=========
* Async `ChannelMonitorUpdate` persistence operations which complete, but are
not marked as complete in a persisted `ChannelManager` prior to restart,
followed immediately by a block connection and then another restart could
result in some channel operations hanging leading for force-closures (#4377).
* If an MPP payment is claimed but `ChannelMonitorUpdate`s for some parts are
still being completed asynchronously, further channel updates (e.g.
forwarding another payment) are pending and the node restarts, the channel
could have become stuck (#4520).
* The presence of unconfirmed transactions actually no longer causes
`ElectrumSyncClient` to spuriously fail to sync (#4590).
* `FilesystemStore::list_all_keys` will no longer fail if there are stale
intermediate files lying around from a previous unclean shutdown (#4618).
* When forwarding an HTLC while in a blinded path with proportional fees over
200%, LDK will no longer spuriously allow a forward that pays us 1 msat too
little in fees (#4697).
* Fixed a rare case where a channel could get stuck on reconnect when using
both async `ChannelMonitorUpdate` persistence and async signing (#4684).
* `Event::PaymentSent::fee_paid_msat` is no longer `None` in cases where
`ChannelManager::abandon_payment` was called before the payment ultimately
completes anyway (#4651).
* Syncing a `ChainMonitor` using the `Confirm` trait will no longer write some
full `ChannelMonitor`s to disk several times per block (#4544).
* `OMDomainResolver` now correctly accounts for failed queries when rate
limiting, ensuring we continue to respond to queries after failures (#4591).
* Calling `ChannelManager::send_payment_with_route` without a `route_params`
and with an invalid `Route` will no longer panic (#4707).
* `lightning-custom-message`'s handling of `peer_connected` events now ensures
that sub-handlers will see a `peer_disconnected` event if a different
sub-handler refused the connection by `Err`ing `peer_connected` (#4595).
* Incomplete MPP keysend payments will no longer see their HTLCs held until
expiry (#4558).
* `InvoiceRequestBuilder` will no longer accept a `quantity` of `0` for a
BOLT 12 `Offer`, allowing any quantity up to a bound (#4667).
* `lightning-custom-message` handlers that return `Ok(None)` when asked to
deserialize a message in their defined range no longer cause panics (#4709).
* Several spurious debug assertions were fixed (#4537, #4618).
Security
========
0.1.10 fixes a sanitization issue and several denial-of-service vulnerabilities.
* `Bolt11Invoice::recover_payee_pub_key` no longer panics if called on an
invoice which set an explicit public key, rather than relying on public key
recovery. This method is called from `payment_parameters_from_invoice` and
`payment_parameters_from_variable_amount_invoice` (#4717).
* Maliciously-crafted unpayable invoices which have overflowing feerates will
no longer cause an `unwrap` failure panic (#4716).
* `possiblyrandom` did not properly generate random data except when it was
explicitly configured to. By default this means LDK is vulnerable to various
HashDoS attacks (#4719).
* `OMNameResolver` will no longer panic when looking up payment instructions
which include unicode characters at the start of a TXT record (#4718).
* `PrintableString` did not properly sanitize unicode format characters,
allowing an attacker to corrupt the rendering of logs or UI (#4593, #4605).
* RGS data is now limited in how large of a graph it is able to cause a client
to store in memory. Note that RGS data is still considered a DoS vector in
general and you should only use semi-trusted RGS data (#4713).
* Counterparty-provided strings in failure messages are no longer logged in
full, reducing the ability of such a counterparty to spam our logs (#4714).
* Reading a corrupted `ChannelManager` or `ProbabilisticScorer` can no longer
cause us to allocate large amounts of memory (#4712).
Thanks to Project Loupe for reporting most of the issues fixed in this release.
TheBlueMatt added a commit to TheBlueMatt/rust-lightning that referenced this pull request Jun 23, 2026
v0.2.3 - Jun 18, 2026 - "Through the Loupe"
API Updates
===========
* `DefaultMessageRouter` will now always generate blinded message paths that
provide no privacy (where our node is the introduction node) for nodes with
public channels. This works around an issue which will appear for any nodes
with LND peers that enable onion messaging - such peers will refuse to
forward BOLT 12 messages from unknown third parties, which most BOLT 12
payers rely on today (lightningdevkit#4647).
* Explicit `amount_msats` of 0 is rejected in BOLT 12 `Offer`s; `OfferBuilder`
now maps 0-amounts to an amount of `None` (lightningdevkit#4324).
Bug Fixes
=========
* `Features::supports_zero_conf` no longer clears the `ZeroConf` features and
`Features::requires_zero_conf` now correctly reports required, rather than
supported, status (lightningdevkit#4517).
* If an MPP payment is claimed but `ChannelMonitorUpdate`s for some parts are
still being completed asynchronously, further channel updates (e.g.
forwarding another payment) are pending and the node restarts, the channel
could have become stuck (lightningdevkit#4520).
* The presence of unconfirmed transactions actually no longer causes
`ElectrumSyncClient` to spuriously fail to sync (lightningdevkit#4590).
* LSPS1, LSPS2, and LSPS5 persistence will no longer get stuck and refuse to
persist again after a single failure from the KVStore (lightningdevkit#4597, lightningdevkit#4282).
* Dropping the future returned by
`OutputSweeper::regenerate_and_broadcast_spend_if_necessary` no longer
results in future calls to the same method being spuriously ignored (lightningdevkit#4598).
* Used async-receive offers are no longer refreshed on every timer tick once
their refresh time is reached (lightningdevkit#4672).
* `FilesystemStore::list_all_keys` will no longer fail if there are stale
intermediate files lying around from a previous unclean shutdown (lightningdevkit#4618).
* When forwarding an HTLC while in a blinded path with proportional fees over
200%, LDK will no longer spuriously allow a forward that pays us 1 msat too
little in fees (lightningdevkit#4697).
* Fixed a rare case where a channel could get stuck on reconnect when using
both async `ChannelMonitorUpdate` persistence and async signing (lightningdevkit#4684).
* If we had exactly zero balance in a zero-fee-commitment channel, the
counterparty was able to splice all of their balance out, violating the
reserve requirements they'd otherwise be forced to keep (lightningdevkit#4580).
* Providing an `Event::HTLCIntercepted` to the `LSPS2ServiceHandler` twice no
longer results in spuriously opening a channel early (lightningdevkit#4656).
* `Event::PaymentSent::fee_paid_msat` is no longer `None` in cases where
`ChannelManager::abandon_payment` was called before the payment ultimately
completes anyway (lightningdevkit#4651).
* `AnchorDescriptor::previous_utxo` now provides the correct `script_pubkey`
for non-zero-commitment-fee anchor channels (lightningdevkit#4669).
* Syncing a `ChainMonitor` using the `Confirm` trait will no longer write some
full `ChannelMonitor`s to disk several times per block (lightningdevkit#4544).
* `OMDomainResolver` now correctly accounts for failed queries when rate
limiting, ensuring we continue to respond to queries after failures (lightningdevkit#4591).
* Calling `ChannelManager::send_payment_with_route` without a `route_params`
and with an invalid `Route` will no longer panic (lightningdevkit#4707).
* `LSPS2ServiceHandler::channel_open_failed` now correctly fails intercepted
HTLCs rather than allowing them to fail just before expiry (lightningdevkit#4677).
* `StaticInvoice::is_offer_expired` was corrected to check offer, rather than
static invoice, expiry (lightningdevkit#4594).
* `lightning-custom-message`'s handling of `peer_connected` events now ensures
that sub-handlers will see a `peer_disconnected` event if a different
sub-handler refused the connection by `Err`ing `peer_connected` (lightningdevkit#4595).
* Replay protection for LSPS5 signatures now detects replays which are only
different in the encoded signature's case (lightningdevkit#4701).
* When `lightning-liquidity` is configured in the background processor, there
is no longer a stream of `Persisting LiquidityManager...` log spam (lightningdevkit#4246).
* Incomplete MPP keysend payments will no longer see their HTLCs held until
expiry (lightningdevkit#4558).
* `InvoiceRequestBuilder` will no longer accept a `quantity` of `0` for a
BOLT 12 `Offer`, allowing any quantity up to a bound (lightningdevkit#4667).
* `lightning-custom-message` handlers that return `Ok(None)` when asked to
deserialize a message in their defined range no longer cause panics (lightningdevkit#4709).
* Several spurious debug assertions were fixed (lightningdevkit#4537, lightningdevkit#4618, lightningdevkit#4026)
Security
========
0.2.3 fixes several underestimates of the anchor reserves required to ensure we
can reliably close channels, several denial-of-service vulnerabilities and a
sanitization issue.
* `Bolt11Invoice::recover_payee_pub_key` no longer panics if called on an
invoice which set an explicit public key, rather than relying on public key
recovery. Note that this method is called from
`PaymentParameters::from_bolt11_invoice` (lightningdevkit#4717).
* Maliciously-crafted unpayable invoices which have overflowing feerates will
no longer cause an `unwrap` failure panic (lightningdevkit#4716).
* Parsing an `LSPSDateTime` which is before 1970 no longer panics. This is
reachable when parsing messages from counterparties (lightningdevkit#4715).
* `possiblyrandom` did not properly generate random data except when it was
explicitly configured to. By default this means LDK is vulnerable to various
HashDoS attacks (lightningdevkit#4719).
* `OMNameResolver` will no longer panic when looking up payment instructions
which include unicode characters at the start of a TXT record (lightningdevkit#4718).
* When using the `anchor_channel_reserves` module to calculate reserves
required to pay for fees when closing anchor channels, zero-fee-commitment
channels were not considered. This could allow a counterparty to open many
channels, leaving us unable to properly force-close (lightningdevkit#4592).
* The `anchor_channel_reserves` module overestimated the value of `Utxo`s in
the wallet by ignoring the `TxIn` cost to spend them (lightningdevkit#4670).
* `PrintableString` did not properly sanitize unicode format characters,
allowing an attacker to corrupt the rendering of logs or UI (lightningdevkit#4593, lightningdevkit#4605).
* RGS data is now limited in how large of a graph it is able to cause a client
to store in memory. Note that RGS data is still considered a DoS vector in
general and you should only use semi-trusted RGS data (lightningdevkit#4713).
* Counterparty-provided strings in failure messages are no longer logged in
full, reducing the ability of such a counterparty to spam our logs (lightningdevkit#4714).
* Reading a corrupted `ChannelManager` or `ProbabilisticScorer` can no longer
cause us to allocate large amounts of memory (lightningdevkit#4712).
Thanks to Project Loupe for reporting most of the issues fixed in this release.
Conflicts resolved in:
* lightning/src/chain/channelmonitor.rs
* lightning/src/events/mod.rs
* lightning/src/ln/channelmanager.rs
* lightning/src/ln/mod.rs
* lightning/src/ln/offers_tests.rs
* lightning/src/ln/onion_utils.rs
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@tnull@ldk-reviews-bot@ldk-claude-review-bot@TheBlueMatt