Update module google.golang.org/grpc to v1.83.2 [SECURITY] (release/v2.12) by renovate-rancher[bot] · Pull Request #613 · rancher/machine

renovate-rancher · 2026-09-03T05:36:37Z

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This PR body was truncated due to platform limits.

This PR contains the following updates:

Package	Change	Age	Confidence
google.golang.org/grpc	`v1.71.0` → `v1.83.2`

gRPC-Go: Heap Memory Exhaustion (OOM) via HTTP/2 DATA Frame Fragmentation

CVE-2026-84304 / GHSA-vp52-pcj8-j9qc

More information

Details

Impact

An unauthenticated remote attacker can initiate a gRPC stream and purposefully fragment their payload into millions of tiny (e.g., 1-byte) HTTP/2 DATA frames. Even if the total payload volume falls within the configured connection and stream flow-control windows, each independent fragment incurs memory overhead due to internal tracking structures and queue allocation.

Repeated fragmentation massively inflates the heap space consumed by the stream. An attacker multiplexing multiple concurrent streams can exhaust the memory bounds of the runtime, forcing a runtime panic or OutOfMemory condition and leading to a remote Denial of Service (DoS).

Patches

The change to fix this issue is merged in master and a patch release, 1.83.1, has been published that contains this fix.

Workarounds

This vulnerability is mitigated by implementing receive buffer compaction. Consecutive small data buffers are automatically coalesced into larger buffers from a shared pool once the overhead is perceived to be excessive relative to actual payload data, drastically minimizing per-frame memory overheads.

This behavior is enabled by default. A temporary escape hatch is provided via the environment variable GRPC_GO_EXPERIMENTAL_ENABLE_RECEIVE_BUFFER_COMPACTION=false to disable the feature if unforeseen issues arise, but it will be removed in a future release.

Severity

CVSS Score: 8.7 / 10 (High)
Vector String: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

gRPC-Go xDS servers: Denial of Service (DoS) via crash due to missing `:authority` and `Host` headers

CVE-2026-84445 / GHSA-2v4p-qf9q-27wj

More information

Details

A vulnerability exists in gRPC-Go servers configured with xds.NewGRPCServer() where a crafted request missing both :authority and Host headers can cause a server panic, resulting in a Denial of Service (DoS).

Servers built with xds.NewGRPCServer install an xDS routing interceptor on every RPC. This interceptor looks up the request’s :authority header to pick a virtual host. The HTTP/2 server transport previously accepted requests that had neither :authority nor Host. When this happened, the xDS routing interceptor attempted to access the first element of an empty slice of authorities, leading to an index out of bounds panic. Since the per-RPC goroutine does not recover from panics, the entire server process would terminate.

This panic occurs in the interceptor pipeline, meaning the transport credentials handshake (TLS, mTLS, or ALTS) and HTTP/2 connection establishment must complete successfully before the crafted request can reach this logic.

Insecure/Standard TLS: If the server permits insecure (plaintext) connections or standard credentials (where client certs are not checked), any unauthenticated remote attacker can trigger the crash.
mTLS / ALTS: If strict transport-level authentication is enforced at the network edge or transport layer (e.g., requiring a valid client certificate), the attacker must possess valid transport credentials to initiate the stream and trigger the panic.

Impact

An attacker can cause a complete outage of the gRPC server by sending a request missing both :authority and Host headers, provided they can successfully establish a transport connection.

Patches

The issue has been addressed in master (and backported to 1.83.2 and 1.82.2). The fix updates the HTTP/2 transport layer to reject requests missing both :authority and Host headers early, maintaining consistency with and other gRPC language implementations.

Severity

High

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

gRPC-Go has an authorization bypass via missing leading slash in :path

CVE-2026-33186 / GHSA-p77j-4mvh-x3m3 / GO-2026-4762

More information

Details

Impact

What kind of vulnerability is it? Who is impacted?

It is an Authorization Bypass resulting from Improper Input Validation of the HTTP/2 :path pseudo-header.

The gRPC-Go server was too lenient in its routing logic, accepting requests where the :path omitted the mandatory leading slash (e.g., Service/Method instead of /Service/Method). While the server successfully routed these requests to the correct handler, authorization interceptors (including the official grpc/authz package) evaluated the raw, non-canonical path string. Consequently, "deny" rules defined using canonical paths (starting with /) failed to match the incoming request, allowing it to bypass the policy if a fallback "allow" rule was present.

Who is impacted?
This affects gRPC-Go servers that meet both of the following criteria:

They use path-based authorization interceptors, such as the official RBAC implementation in google.golang.org/grpc/authz or custom interceptors relying on info.FullMethod or grpc.Method(ctx).
Their security policy contains specific "deny" rules for canonical paths but allows other requests by default (a fallback "allow" rule).

The vulnerability is exploitable by an attacker who can send raw HTTP/2 frames with malformed :path headers directly to the gRPC server.

Patches

Has the problem been patched? What versions should users upgrade to?

Yes, the issue has been patched. The fix ensures that any request with a :path that does not start with a leading slash is immediately rejected with a codes.Unimplemented error, preventing it from reaching authorization interceptors or handlers with a non-canonical path string.

Users should upgrade to the following versions (or newer):

v1.79.3
The latest master branch.

It is recommended that all users employing path-based authorization (especially grpc/authz) upgrade as soon as the patch is available in a tagged release.

Workarounds

Is there a way for users to fix or remediate the vulnerability without upgrading?

While upgrading is the most secure and recommended path, users can mitigate the vulnerability using one of the following methods:

1. Use a Validating Interceptor (Recommended Mitigation)

Add an "outermost" interceptor to your server that validates the path before any other authorization logic runs:

funcpathValidationInterceptor(ctx context.Context, reqany, info*grpc.UnaryServerInfo, handler grpc.UnaryHandler) (any, error) {
ifinfo.FullMethod==""||info.FullMethod[0] !='/' {
returnnil, status.Errorf(codes.Unimplemented, "malformed method name")
} returnhandler(ctx, req)
}
// Ensure this is the FIRST interceptor in your chains:=grpc.NewServer(
grpc.ChainUnaryInterceptor(pathValidationInterceptor, authzInterceptor),
)

2. Infrastructure-Level Normalization

If your gRPC server is behind a reverse proxy or load balancer (such as Envoy, NGINX, or an L7 Cloud Load Balancer), ensure it is configured to enforce strict HTTP/2 compliance for pseudo-headers and reject or normalize requests where the :path header does not start with a leading slash.

3. Policy Hardening

Switch to a "default deny" posture in your authorization policies (explicitly listing all allowed paths and denying everything else) to reduce the risk of bypasses via malformed inputs.

Severity

CVSS Score: 9.1 / 10 (Critical)
Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

References

This data is provided by OSV and the GitHub Advisory Database (CC-BY 4.0).

Authorization bypass in gRPC-Go via missing leading slash in :path in google.golang.org/grpc

CVE-2026-33186 / GHSA-p77j-4mvh-x3m3 / GO-2026-4762

More information

Details

Authorization bypass in gRPC-Go via missing leading slash in :path in google.golang.org/grpc

Severity

Unknown

References

https://github.com/grpc/grpc-go/security/advisories/GHSA-p77j-4mvh-x3m3

This data is provided by OSV and the Go Vulnerability Database (CC-BY 4.0).

gRPC-Go: xDS RBAC and HTTP/2 Vulnerabilities

GHSA-hrxh-6v49-42gf / GO-2026-6061

More information

Details

Multiple security vulnerabilities have been identified and addressed in grpc-go affecting the xDS RBAC authorization engine (internal/xds/rbac) and the HTTP/2 transport server implementation (internal/transport). These vulnerabilities could result in:

Authorization Bypass (Fail-Open) when translating xDS RBAC policies containing Metadata or RequestedServerName fields.
Denial of Service (High CPU Consumption) due to an HTTP/2 Rapid Reset mitigation bypass during client-initiated stream resets.
Denial of Service (Server Panic) when parsing crafted xDS RBAC policies containing NOT rules around unsupported fields.

Impact

What kind of vulnerability is it? Who is impacted?

xDS RBAC Authorization Bypass via `Metadata` & `RequestedServerName` matchers

Affected Component: xDS RBAC
Impact: When building policy matchers for gRPC RBAC from xDS configurations, unsupported permission and principal rules (specifically Metadata and RequestedServerName) were silently ignored and treated as no-ops.
- If an authorization policy relied purely on these matchers for access control, treating those rules as no-ops effectively removed the restrictions.
If these unsupported rules were nested inside logical NOT rules (Permission_NotRule / Principal_NotId) or multi-condition OR/AND rules, silently dropping them changed the boolean logic flow of the authorization engine.

As a result, policy evaluation decisions could fail open, allowing unauthorized clients to access protected gRPC services or resources.

HTTP/2 Rapid Reset Mitigation Bypass / Denial of Service via Stream Aborts

Affected Component: HTTP/2 transport
Impact: Earlier mitigations in grpc-go for HTTP/2 Rapid Reset only applied threshold checks to items that directly resulted in control frames being written back to the wire, such as SETTINGS ACKs or server-initiated RST_STREAMs.

When a client initiated a rapid flood of stream creation (HEADERS) immediately followed by stream termination RST_STREAM, items queued up in the control buffer without counting against the transport response frame threshold. An attacker can repeatedly trigger this flood sequence to bypass reader blocking, resulting in high CPU usage, and Denial of Service (DoS).

Denial of Service (Panic) in xDS RBAC Engine via Unsupported Fields inside NOT Rules

Affected Component: xDS RBAC
Impact: The xDS RBAC policy translators recursively generate matchers for nested rules. When a NOT rule wrapped an unsupported or unhandled field (such as SourcedMetadata), the recursive step returned an empty matcher. This could result in a runtime panic when the RBAC engine attempts to authorize an incoming request.

An attacker or misconfigured/malicious xDS management server delivering an LDS/RDS update containing a NOT rule around an unhandled field causes the gRPC server process to crash immediately (CWE-248 / Denial of Service).

Patches

Has the problem been patched? What versions should users upgrade to?

All three issues have been fixed in master and will be released in 1.82.1 shortly.

Workarounds

Is there a way for users to fix or remediate the vulnerability without upgrading?

If upgrading grpc-go immediately is not possible, apply the following workarounds based on your deployment architecture:

For xDS RBAC Vulnerabilities & Panics: Ensure that upstream xDS management servers do not push RBAC policies containing Metadata, RequestedServerName, or NOT rules wrapping unsupported fields (such as SourcedMetadata) to grpc-go servers.
For HTTP/2 Rapid Reset DOS: Configure upstream reverse proxies or load balancers (such as Envoy) with strict HTTP/2 max_concurrent_streams limits and active rate limiting on RST_STREAM frequency per connection.

Severity

Vulnerability	Qualitative Severity	Approximate CVSS v3.1 Score	Primary Impact
xDS RBAC Authorization Bypass	High	`8.2`	Unauthorized Access / Fail-Open
HTTP/2 Rapid Reset DOS Bypass	High	`7.5`	High CPU Consumption / Denial of Service
xDS RBAC Engine Server Panic	Medium	`5.9`	Process Crash / Denial of Service

Severity

CVSS Score: 8.8 / 10 (High)
Vector String: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N

References

This data is provided by OSV and the GitHub Advisory Database (CC-BY 4.0).

Vulnerabilities in the xDS RBAC authorization engine and the HTTP/2 transport server implementation in google.golang.org/grpc

GHSA-hrxh-6v49-42gf / GO-2026-6061

More information

Details

Vulnerabilities in the xDS RBAC authorization engine and the HTTP/2 transport server implementation in google.golang.org/grpc

Severity

Unknown

References

This data is provided by OSV and the Go Vulnerability Database (CC-BY 4.0).

gRPC-Go xDS servers: Denial of Service (DoS) via crash due to missing `:authority` and `Host` headers

CVE-2026-84445 / GHSA-2v4p-qf9q-27wj

More information

Details

A vulnerability exists in gRPC-Go servers configured with xds.NewGRPCServer() where a crafted request missing both :authority and Host headers can cause a server panic, resulting in a Denial of Service (DoS).

Servers built with xds.NewGRPCServer install an xDS routing interceptor on every RPC. This interceptor looks up the request’s :authority header to pick a virtual host. The HTTP/2 server transport previously accepted requests that had neither :authority nor Host. When this happened, the xDS routing interceptor attempted to access the first element of an empty slice of authorities, leading to an index out of bounds panic. Since the per-RPC goroutine does not recover from panics, the entire server process would terminate.

This panic occurs in the interceptor pipeline, meaning the transport credentials handshake (TLS, mTLS, or ALTS) and HTTP/2 connection establishment must complete successfully before the crafted request can reach this logic.

Insecure/Standard TLS: If the server permits insecure (plaintext) connections or standard credentials (where client certs are not checked), any unauthenticated remote attacker can trigger the crash.
mTLS / ALTS: If strict transport-level authentication is enforced at the network edge or transport layer (e.g., requiring a valid client certificate), the attacker must possess valid transport credentials to initiate the stream and trigger the panic.

Impact

An attacker can cause a complete outage of the gRPC server by sending a request missing both :authority and Host headers, provided they can successfully establish a transport connection.

Patches

The issue has been addressed in master (and backported to 1.83.2 and 1.82.2). The fix updates the HTTP/2 transport layer to reject requests missing both :authority and Host headers early, maintaining consistency with and other gRPC language implementations.

Severity

High

References

This data is provided by OSV and the GitHub Advisory Database (CC-BY 4.0).

gRPC-Go: xDS RBAC HTTP Filter bypass via mixed-case Header Matching and gRFC A41 validation evasion

CVE-2026-84303 / GHSA-qc2q-p7wx-3px3

More information

Details

Summary

A vulnerability in the xDS RBAC HTTP filter implementation in grpc-go allows remote attackers to bypass authorization policies (specifically DENY rules) by using mixed-case or canonical-case header matchers (e.g., X-Role instead of x-role). Additionally, the safety guards introduced by gRFC A41 to block grpc- prefixed headers can be evaded via variations in casing (e.g., Grpc-Status).

Impact

When an operator defines an RBAC policy referencing headers containing uppercase letters (e.g. X-Role), grpc-go fails to match incoming metadata keys because they are unconditionally lowercased. Because of this case-sensitivity mismatch, a policy designed to block requests containing specific header values fails open: the rule is evaluated as a non-match, and traffic that should have been rejected is served.

Furthermore, gRFC A41 requires rejecting configuration schemas specifying header matchers starting with grpc-. Because this check is executed case-sensitively in grpc-go, attackers can bypass the validation by specifying titles like Grpc-Status.

Patches

The problem is fixed in master and in the 1.83.1 release.

Severity

CVSS Score: 6.3 / 10 (Medium)
Vector String: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

References

This data is provided by OSV and the GitHub Advisory Database (CC-BY 4.0).

gRPC-Go: Heap Memory Exhaustion (OOM) via HTTP/2 DATA Frame Fragmentation

CVE-2026-84304 / GHSA-vp52-pcj8-j9qc

More information

Details

Impact

An unauthenticated remote attacker can initiate a gRPC stream and purposefully fragment their payload into millions of tiny (e.g., 1-byte) HTTP/2 DATA frames. Even if the total payload volume falls within the configured connection and stream flow-control windows, each independent fragment incurs memory overhead due to internal tracking structures and queue allocation.

Repeated fragmentation massively inflates the heap space consumed by the stream. An attacker multiplexing multiple concurrent streams can exhaust the memory bounds of the runtime, forcing a runtime panic or OutOfMemory condition and leading to a remote Denial of Service (DoS).

Patches

The change to fix this issue is merged in master and a patch release, 1.83.1, has been published that contains this fix.

Workarounds

This vulnerability is mitigated by implementing receive buffer compaction. Consecutive small data buffers are automatically coalesced into larger buffers from a shared pool once the overhead is perceived to be excessive relative to actual payload data, drastically minimizing per-frame memory overheads.

This behavior is enabled by default. A temporary escape hatch is provided via the environment variable GRPC_GO_EXPERIMENTAL_ENABLE_RECEIVE_BUFFER_COMPACTION=false to disable the feature if unforeseen issues arise, but it will be removed in a future release.

Severity

CVSS Score: 8.7 / 10 (High)
Vector String: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

References

This data is provided by OSV and the GitHub Advisory Database (CC-BY 4.0).

Release Notes

grpc/grpc-go (google.golang.org/grpc)

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gRPC-Go: Heap Memory Exhaustion (OOM) via HTTP/2 DATA Frame Fragmentation

Details

Impact

Patches

Workarounds

Severity

References

gRPC-Go xDS servers: Denial of Service (DoS) via crash due to missing :authority and Host headers

Details

Impact

Patches

Severity

References

gRPC-Go has an authorization bypass via missing leading slash in :path

Details

Impact

Patches

Workarounds

1. Use a Validating Interceptor (Recommended Mitigation)

2. Infrastructure-Level Normalization

3. Policy Hardening

Severity

References

Authorization bypass in gRPC-Go via missing leading slash in :path in google.golang.org/grpc

Details

Severity

References

gRPC-Go: xDS RBAC and HTTP/2 Vulnerabilities

Details

Impact

xDS RBAC Authorization Bypass via Metadata & RequestedServerName matchers

HTTP/2 Rapid Reset Mitigation Bypass / Denial of Service via Stream Aborts

Denial of Service (Panic) in xDS RBAC Engine via Unsupported Fields inside NOT Rules

Patches

Workarounds

Severity

Severity

References

Vulnerabilities in the xDS RBAC authorization engine and the HTTP/2 transport server implementation in google.golang.org/grpc

Details

Severity

References

gRPC-Go xDS servers: Denial of Service (DoS) via crash due to missing :authority and Host headers

Details

Impact

Patches

Severity

References

gRPC-Go: xDS RBAC HTTP Filter bypass via mixed-case Header Matching and gRFC A41 validation evasion

Details

Summary

Impact

Patches

Severity

References

gRPC-Go: Heap Memory Exhaustion (OOM) via HTTP/2 DATA Frame Fragmentation

Details

Impact

Patches

Workarounds

Severity

References

Release Notes

v1.83.2: Release 1.83.2

Security

v1.83.1: Release 1.83.1

Security

Performance

v1.83.0: Release 1.83.0

Security

New Features

Bug Fixes

v1.82.2: Release 1.82.2

Security

v1.82.1: Release 1.82.1

Security

renovate-rancherBot commented Sep 3, 2026•
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gRPC-Go xDS servers: Denial of Service (DoS) via crash due to missing `:authority` and `Host` headers

xDS RBAC Authorization Bypass via `Metadata` & `RequestedServerName` matchers

gRPC-Go xDS servers: Denial of Service (DoS) via crash due to missing `:authority` and `Host` headers

`v1.83.2`: Release 1.83.2

`v1.83.1`: Release 1.83.1

`v1.83.0`: Release 1.83.0

`v1.82.2`: Release 1.82.2

`v1.82.1`: Release 1.82.1

`v1.82.0`: Release 1.82.0

`v1.81.1`: Release 1.81.1

`v1.81.0`: Release 1.81.0

`v1.80.0`: Release 1.80.0

`v1.79.3`: Release 1.79.3

`v1.79.2`: Release 1.79.2

`v1.79.1`: Release 1.79.1

`v1.79.0`: Release 1.79.0

`v1.78.0`: Release 1.78.0

`v1.77.0`: Release 1.77.0

renovate-rancherBot commented Sep 3, 2026•
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