fix(backend): Fix cross-origin handshake bypass - #9145

Merged
dominic-clerk merged 3 commits into
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dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts
Jul 18, 2026
Merged

fix(backend): Fix cross-origin handshake bypass#9145
dominic-clerk merged 3 commits into
mainfrom
dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts

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@dominic-clerkdominic-clerk commented Jul 13, 2026

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Description

Fix a cross-origin handshake bypass where isKnownClerkReferrer() trusted overly broad referrer hosts as Clerk-owned: any accounts.* host (e.g. accounts.attacker.com), plus dev account-portal domains (*.accounts.dev and legacy suffixes) on production instances. These let unrelated origins skip the handshake and its session-freshness check. The referrer is now trusted only for the accounts portal derived from the instance's frontend API, plus dev account-portal domains on non-production instances.

Fixes SDK-143

Checklist

  • pnpm test runs as expected.
  • pnpm build runs as expected.
  • (If applicable) JSDoc comments have been added or updated for any package exports
  • (If applicable) Documentation has been updated

Type of change

  • 🐛 Bug fix
  • 🌟 New feature
  • 🔨 Breaking change
  • 📖 Refactoring / dependency upgrade / documentation
  • other:

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ProjectDeploymentActionsUpdated (UTC)
clerk-js-sandboxReadyReadyPreview, CommentJul 17, 2026 10:57pm
swingsetReadyReadyPreview, CommentJul 17, 2026 10:57pm

Request Review

Fix a cross-origin handshake bypass where `isKnownClerkReferrer()`
trusted overly broad referrer hosts as Clerk-owned: any `accounts.*`
host (e.g. `accounts.attacker.com`), plus dev account-portal domains
(`*.accounts.dev` and legacy suffixes) on production instances. These
let unrelated origins skip the handshake and its session-freshness check.
The referrer is now trusted only for the accounts portal derived from
the instance's frontend API, plus dev account-portal domains on
non-production instances.
@dominic-clerk
dominic-clerkforce-pushed the dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts branch from db0893d to 67c3fdcCompareJuly 13, 2026 14:11
@dominic-clerkdominic-clerk changed the title fix(backend): Fix cross-origin handshakre bypassfix(backend): Fix cross-origin handshake bypassJul 13, 2026
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🦋 Changeset detected

Latest commit: 0cd1824

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 10 packages
NameType
@clerk/backendMinor
@clerk/astroPatch
@clerk/expressPatch
@clerk/fastifyPatch
@clerk/honoPatch
@clerk/nextjsPatch
@clerk/nuxtPatch
@clerk/react-routerPatch
@clerk/tanstack-react-startPatch
@clerk/testingPatch

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Click here if you're a maintainer who wants to add another changeset to this PR

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@clerk/chrome-extension

npm i https://pkg.pr.new/@clerk/chrome-extension@9145

@clerk/clerk-js

npm i https://pkg.pr.new/@clerk/clerk-js@9145

@clerk/electron

npm i https://pkg.pr.new/@clerk/electron@9145

@clerk/electron-passkeys

npm i https://pkg.pr.new/@clerk/electron-passkeys@9145

@clerk/eslint-plugin

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@clerk/expo

npm i https://pkg.pr.new/@clerk/expo@9145

@clerk/expo-passkeys

npm i https://pkg.pr.new/@clerk/expo-passkeys@9145

@clerk/express

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@clerk/fastify

npm i https://pkg.pr.new/@clerk/fastify@9145

@clerk/hono

npm i https://pkg.pr.new/@clerk/hono@9145

@clerk/localizations

npm i https://pkg.pr.new/@clerk/localizations@9145

@clerk/nextjs

npm i https://pkg.pr.new/@clerk/nextjs@9145

@clerk/nuxt

npm i https://pkg.pr.new/@clerk/nuxt@9145

@clerk/react

npm i https://pkg.pr.new/@clerk/react@9145

@clerk/react-router

npm i https://pkg.pr.new/@clerk/react-router@9145

@clerk/shared

npm i https://pkg.pr.new/@clerk/shared@9145

@clerk/tanstack-react-start

npm i https://pkg.pr.new/@clerk/tanstack-react-start@9145

@clerk/testing

npm i https://pkg.pr.new/@clerk/testing@9145

@clerk/ui

npm i https://pkg.pr.new/@clerk/ui@9145

@clerk/upgrade

npm i https://pkg.pr.new/@clerk/upgrade@9145

@clerk/vue

npm i https://pkg.pr.new/@clerk/vue@9145

commit: 0cd1824

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API Changes Report

Generated by Break Check on 2026-07-17T22:58:31.902Z

Summary

MetricCount
Packages analyzed19
Packages with changes0
🔴 Breaking changes0
🟡 Non-breaking changes0
🟢 Additions0

No API Changes Detected

All packages have stable APIs with no detected changes.


Report generated by Break Check

Last ran on 0cd1824.

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Review Change Stack

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info
⚙️ Run configuration

Configuration used: Repository YAML (base), Organization UI (inherited)

Review profile: CHILL

Plan: Pro Plus

Run ID: cf939caa-c68e-48a1-ac14-cc89d6e1c727

📥 Commits

Reviewing files that changed from the base of the PR and between 9bee8e1 and 0cd1824.

📒 Files selected for processing (1)
  • packages/backend/src/tokens/__tests__/request.test.ts
🔗 Linked repositories identified

CodeRabbit considers these linked repositories for cross-repo context during reviews:

  • clerk/clerk_go(manual)
  • clerk/dashboard(manual)
  • clerk/accounts(manual)
  • clerk/backoffice(manual)
  • clerk/clerk(manual)
  • clerk/clerk-docs(manual)
  • clerk/cloudflare-workers(manual)
🚧 Files skipped from review as they are similar to previous changes (1)
  • packages/backend/src/tokens/tests/request.test.ts

📝 Walkthrough

Walkthrough

The backend now restricts trusted Clerk referrers to instance-derived accounts portals, permits development portals only for non-production instances, and expands cross-origin handshake tests for unrelated and production referrers.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Suggested reviewers:wobsoriano

🚥 Pre-merge checks | ✅ 5
✅ Passed checks (5 passed)
Check nameStatusExplanation
Title check✅ PassedThe title clearly summarizes the main change: fixing a backend cross-origin handshake bypass.
Description check✅ PassedThe description matches the changeset and explains the handshake bypass fix and its scope.
Docstring Coverage✅ PassedNo functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check✅ PassedCheck skipped because no linked issues were found for this pull request.
Out of Scope Changes check✅ PassedCheck skipped because no linked issues were found for this pull request.

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});
});

test('does not trigger handshake when referer is from production accounts portal', async () => {

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We revert the logic of this test because it tested that example.com's account portal wouldn't trigger a handshake on another (primary.com's) instance.

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🧹 Nitpick comments (2)
packages/backend/src/tokens/__tests__/request.test.ts (1)

2091-2139: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

Weak assertion in the new "does not trigger handshake" tests.

Both new tests only assert requestState.reason is not PrimaryDomainCrossOriginSync. This doesn't confirm the request actually reached a signed-in state — a regression producing some other error/reason would still pass. Consider asserting the actual expected signed-in shape (e.g. status/isSignedIn), similar to how the sibling "triggers" tests use the full toMatchHandshake matcher.

As per coding guidelines: "Unit tests are required for all new functionality... Verify proper error handling and edge cases."

✅ Example strengthened assertion
- expect(requestState.reason).not.toBe(AuthErrorReason.PrimaryDomainCrossOriginSync);+ expect(requestState.reason).not.toBe(AuthErrorReason.PrimaryDomainCrossOriginSync);+ expect(requestState.status).toBe(AuthStatus.SignedIn);
🤖 Prompt for AI Agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
In `@packages/backend/src/tokens/__tests__/request.test.ts` around lines 2091 -
2139, Strengthen both dev accounts portal tests around authenticateRequest by
asserting the complete expected signed-in request state, using the existing
toMatchHandshake matcher or the established status/isSignedIn assertions from
sibling tests. Keep the checks for both current and legacy referer formats, and
ensure each test verifies successful authentication rather than only excluding
PrimaryDomainCrossOriginSync.

Source: Coding guidelines

packages/backend/src/tokens/authenticateContext.ts (1)

218-224: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

JSDoc no longer matches the tightened trust behavior.

The doc comment still says referrer trust "includes both development and production account portal domains" unconditionally, but the implementation below now only trusts dev account-portal domains when instanceType !== 'production', and no longer trusts any accounts.* host. If this method's JSDoc is surfaced in generated reference docs, it should be updated to reflect the new production/non-production distinction; if AuthenticateContext is purely internal, this may not apply — could you confirm which is the case?

As per path instructions: "If a PR adds or changes public/reference-facing API surface area, check whether the corresponding JSDoc is present, accurate, and aligned with the implementation... When unsure whether a symbol is public/reference-facing, ask for clarification instead of asserting that documentation is required."

🤖 Prompt for AI Agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
In `@packages/backend/src/tokens/authenticateContext.ts` around lines 218 - 224,
Confirm whether the referrer-validation method on AuthenticateContext is
public/reference-facing; if so, update its JSDoc to state that only
non-production instances trust development account-portal domains, production
instances do not trust them, and FAPI domains remain supported. If
AuthenticateContext is internal, leave the documentation unchanged.

Source: Path instructions

🤖 Prompt for all review comments with AI agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
Nitpick comments:
In `@packages/backend/src/tokens/__tests__/request.test.ts`:
- Around line 2091-2139: Strengthen both dev accounts portal tests around
authenticateRequest by asserting the complete expected signed-in request state,
using the existing toMatchHandshake matcher or the established status/isSignedIn
assertions from sibling tests. Keep the checks for both current and legacy
referer formats, and ensure each test verifies successful authentication rather
than only excluding PrimaryDomainCrossOriginSync.
In `@packages/backend/src/tokens/authenticateContext.ts`:
- Around line 218-224: Confirm whether the referrer-validation method on
AuthenticateContext is public/reference-facing; if so, update its JSDoc to state
that only non-production instances trust development account-portal domains,
production instances do not trust them, and FAPI domains remain supported. If
AuthenticateContext is internal, leave the documentation unchanged.

ℹ️ Review info
⚙️ Run configuration

Configuration used: Repository YAML (base), Repository UI (inherited)

Review profile: CHILL

Plan: Pro Plus

Run ID: 3656d6fa-398a-4d3b-9669-6c3884df8c9c

📥 Commits

Reviewing files that changed from the base of the PR and between d8fc1d7 and 67c3fdc.

📒 Files selected for processing (3)
  • .changeset/khaki-chairs-kiss.md
  • packages/backend/src/tokens/__tests__/request.test.ts
  • packages/backend/src/tokens/authenticateContext.ts

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Had to rebase because break check somehow reports a breaking change, even when there's none

👍🏼

@dominic-clerk
dominic-clerk merged commit ff5d991 into mainJul 18, 2026
53 checks passed
@dominic-clerk
dominic-clerk deleted the dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts branch July 18, 2026 01:58
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Skip to content

fix(backend): Fix cross-origin handshake bypass - #9145

Merged
dominic-clerk merged 3 commits into
mainfrom
dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts
Jul 18, 2026
Merged

fix(backend): Fix cross-origin handshake bypass#9145
dominic-clerk merged 3 commits into
mainfrom
dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts

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@dominic-clerk

@dominic-clerkdominic-clerk commented Jul 13, 2026

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Description

Fix a cross-origin handshake bypass where isKnownClerkReferrer() trusted overly broad referrer hosts as Clerk-owned: any accounts.* host (e.g. accounts.attacker.com), plus dev account-portal domains (*.accounts.dev and legacy suffixes) on production instances. These let unrelated origins skip the handshake and its session-freshness check. The referrer is now trusted only for the accounts portal derived from the instance's frontend API, plus dev account-portal domains on non-production instances.

Fixes SDK-143

Checklist

  • pnpm test runs as expected.
  • pnpm build runs as expected.
  • (If applicable) JSDoc comments have been added or updated for any package exports
  • (If applicable) Documentation has been updated

Type of change

  • 🐛 Bug fix
  • 🌟 New feature
  • 🔨 Breaking change
  • 📖 Refactoring / dependency upgrade / documentation
  • other:

@vercel

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ProjectDeploymentActionsUpdated (UTC)
clerk-js-sandboxReadyReadyPreview, CommentJul 17, 2026 10:57pm
swingsetReadyReadyPreview, CommentJul 17, 2026 10:57pm

Request Review

Fix a cross-origin handshake bypass where `isKnownClerkReferrer()`
trusted overly broad referrer hosts as Clerk-owned: any `accounts.*`
host (e.g. `accounts.attacker.com`), plus dev account-portal domains
(`*.accounts.dev` and legacy suffixes) on production instances. These
let unrelated origins skip the handshake and its session-freshness check.
The referrer is now trusted only for the accounts portal derived from
the instance's frontend API, plus dev account-portal domains on
non-production instances.
@dominic-clerk
dominic-clerkforce-pushed the dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts branch from db0893d to 67c3fdcCompareJuly 13, 2026 14:11
@dominic-clerkdominic-clerk changed the title fix(backend): Fix cross-origin handshakre bypassfix(backend): Fix cross-origin handshake bypassJul 13, 2026
@changeset-bot

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🦋 Changeset detected

Latest commit: 0cd1824

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 10 packages
NameType
@clerk/backendMinor
@clerk/astroPatch
@clerk/expressPatch
@clerk/fastifyPatch
@clerk/honoPatch
@clerk/nextjsPatch
@clerk/nuxtPatch
@clerk/react-routerPatch
@clerk/tanstack-react-startPatch
@clerk/testingPatch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

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@clerk/astro

npm i https://pkg.pr.new/@clerk/astro@9145

@clerk/backend

npm i https://pkg.pr.new/@clerk/backend@9145

@clerk/chrome-extension

npm i https://pkg.pr.new/@clerk/chrome-extension@9145

@clerk/clerk-js

npm i https://pkg.pr.new/@clerk/clerk-js@9145

@clerk/electron

npm i https://pkg.pr.new/@clerk/electron@9145

@clerk/electron-passkeys

npm i https://pkg.pr.new/@clerk/electron-passkeys@9145

@clerk/eslint-plugin

npm i https://pkg.pr.new/@clerk/eslint-plugin@9145

@clerk/expo

npm i https://pkg.pr.new/@clerk/expo@9145

@clerk/expo-passkeys

npm i https://pkg.pr.new/@clerk/expo-passkeys@9145

@clerk/express

npm i https://pkg.pr.new/@clerk/express@9145

@clerk/fastify

npm i https://pkg.pr.new/@clerk/fastify@9145

@clerk/hono

npm i https://pkg.pr.new/@clerk/hono@9145

@clerk/localizations

npm i https://pkg.pr.new/@clerk/localizations@9145

@clerk/nextjs

npm i https://pkg.pr.new/@clerk/nextjs@9145

@clerk/nuxt

npm i https://pkg.pr.new/@clerk/nuxt@9145

@clerk/react

npm i https://pkg.pr.new/@clerk/react@9145

@clerk/react-router

npm i https://pkg.pr.new/@clerk/react-router@9145

@clerk/shared

npm i https://pkg.pr.new/@clerk/shared@9145

@clerk/tanstack-react-start

npm i https://pkg.pr.new/@clerk/tanstack-react-start@9145

@clerk/testing

npm i https://pkg.pr.new/@clerk/testing@9145

@clerk/ui

npm i https://pkg.pr.new/@clerk/ui@9145

@clerk/upgrade

npm i https://pkg.pr.new/@clerk/upgrade@9145

@clerk/vue

npm i https://pkg.pr.new/@clerk/vue@9145

commit: 0cd1824

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API Changes Report

Generated by Break Check on 2026-07-17T22:58:31.902Z

Summary

MetricCount
Packages analyzed19
Packages with changes0
🔴 Breaking changes0
🟡 Non-breaking changes0
🟢 Additions0

No API Changes Detected

All packages have stable APIs with no detected changes.


Report generated by Break Check

Last ran on 0cd1824.

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Review Change Stack

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info
⚙️ Run configuration

Configuration used: Repository YAML (base), Organization UI (inherited)

Review profile: CHILL

Plan: Pro Plus

Run ID: cf939caa-c68e-48a1-ac14-cc89d6e1c727

📥 Commits

Reviewing files that changed from the base of the PR and between 9bee8e1 and 0cd1824.

📒 Files selected for processing (1)
  • packages/backend/src/tokens/__tests__/request.test.ts
🔗 Linked repositories identified

CodeRabbit considers these linked repositories for cross-repo context during reviews:

  • clerk/clerk_go(manual)
  • clerk/dashboard(manual)
  • clerk/accounts(manual)
  • clerk/backoffice(manual)
  • clerk/clerk(manual)
  • clerk/clerk-docs(manual)
  • clerk/cloudflare-workers(manual)
🚧 Files skipped from review as they are similar to previous changes (1)
  • packages/backend/src/tokens/tests/request.test.ts

📝 Walkthrough

Walkthrough

The backend now restricts trusted Clerk referrers to instance-derived accounts portals, permits development portals only for non-production instances, and expands cross-origin handshake tests for unrelated and production referrers.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Suggested reviewers:wobsoriano

🚥 Pre-merge checks | ✅ 5
✅ Passed checks (5 passed)
Check nameStatusExplanation
Title check✅ PassedThe title clearly summarizes the main change: fixing a backend cross-origin handshake bypass.
Description check✅ PassedThe description matches the changeset and explains the handshake bypass fix and its scope.
Docstring Coverage✅ PassedNo functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check✅ PassedCheck skipped because no linked issues were found for this pull request.
Out of Scope Changes check✅ PassedCheck skipped because no linked issues were found for this pull request.

Comment @coderabbitai help to get the list of available commands.

});
});

test('does not trigger handshake when referer is from production accounts portal', async () => {

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We revert the logic of this test because it tested that example.com's account portal wouldn't trigger a handshake on another (primary.com's) instance.

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🧹 Nitpick comments (2)
packages/backend/src/tokens/__tests__/request.test.ts (1)

2091-2139: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

Weak assertion in the new "does not trigger handshake" tests.

Both new tests only assert requestState.reason is not PrimaryDomainCrossOriginSync. This doesn't confirm the request actually reached a signed-in state — a regression producing some other error/reason would still pass. Consider asserting the actual expected signed-in shape (e.g. status/isSignedIn), similar to how the sibling "triggers" tests use the full toMatchHandshake matcher.

As per coding guidelines: "Unit tests are required for all new functionality... Verify proper error handling and edge cases."

✅ Example strengthened assertion
- expect(requestState.reason).not.toBe(AuthErrorReason.PrimaryDomainCrossOriginSync);+ expect(requestState.reason).not.toBe(AuthErrorReason.PrimaryDomainCrossOriginSync);+ expect(requestState.status).toBe(AuthStatus.SignedIn);
🤖 Prompt for AI Agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
In `@packages/backend/src/tokens/__tests__/request.test.ts` around lines 2091 -
2139, Strengthen both dev accounts portal tests around authenticateRequest by
asserting the complete expected signed-in request state, using the existing
toMatchHandshake matcher or the established status/isSignedIn assertions from
sibling tests. Keep the checks for both current and legacy referer formats, and
ensure each test verifies successful authentication rather than only excluding
PrimaryDomainCrossOriginSync.

Source: Coding guidelines

packages/backend/src/tokens/authenticateContext.ts (1)

218-224: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

JSDoc no longer matches the tightened trust behavior.

The doc comment still says referrer trust "includes both development and production account portal domains" unconditionally, but the implementation below now only trusts dev account-portal domains when instanceType !== 'production', and no longer trusts any accounts.* host. If this method's JSDoc is surfaced in generated reference docs, it should be updated to reflect the new production/non-production distinction; if AuthenticateContext is purely internal, this may not apply — could you confirm which is the case?

As per path instructions: "If a PR adds or changes public/reference-facing API surface area, check whether the corresponding JSDoc is present, accurate, and aligned with the implementation... When unsure whether a symbol is public/reference-facing, ask for clarification instead of asserting that documentation is required."

🤖 Prompt for AI Agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
In `@packages/backend/src/tokens/authenticateContext.ts` around lines 218 - 224,
Confirm whether the referrer-validation method on AuthenticateContext is
public/reference-facing; if so, update its JSDoc to state that only
non-production instances trust development account-portal domains, production
instances do not trust them, and FAPI domains remain supported. If
AuthenticateContext is internal, leave the documentation unchanged.

Source: Path instructions

🤖 Prompt for all review comments with AI agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
Nitpick comments:
In `@packages/backend/src/tokens/__tests__/request.test.ts`:
- Around line 2091-2139: Strengthen both dev accounts portal tests around
authenticateRequest by asserting the complete expected signed-in request state,
using the existing toMatchHandshake matcher or the established status/isSignedIn
assertions from sibling tests. Keep the checks for both current and legacy
referer formats, and ensure each test verifies successful authentication rather
than only excluding PrimaryDomainCrossOriginSync.
In `@packages/backend/src/tokens/authenticateContext.ts`:
- Around line 218-224: Confirm whether the referrer-validation method on
AuthenticateContext is public/reference-facing; if so, update its JSDoc to state
that only non-production instances trust development account-portal domains,
production instances do not trust them, and FAPI domains remain supported. If
AuthenticateContext is internal, leave the documentation unchanged.

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Run ID: 3656d6fa-398a-4d3b-9669-6c3884df8c9c

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  • .changeset/khaki-chairs-kiss.md
  • packages/backend/src/tokens/__tests__/request.test.ts
  • packages/backend/src/tokens/authenticateContext.ts

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Had to rebase because break check somehow reports a breaking change, even when there's none

👍🏼

@dominic-clerk
dominic-clerk merged commit ff5d991 into mainJul 18, 2026
53 checks passed
@dominic-clerk
dominic-clerk deleted the dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts branch July 18, 2026 01:58
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, 'i'); if (__m === '*' || __re.test(location.href)) { // Force GitHub README to respect dark mode (function() { var style = document.createElement('style'); style.textContent = ' .markdown-body { color-scheme: dark light; } .markdown-body pre { background: #161b22 !important; } .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; } .markdown-body table th, .markdown-body table td { border-color: #30363d !important; } .markdown-body img { background: #0d1117; } .markdown-body blockquote { border-left-color: #8b949e; } .markdown-body hr { border-color: #30363d; } '; document.head.appendChild(style); })(); } } catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); } })(); (function(){ try { var __m = "*"; var __re = new RegExp('^' + ".*" + '
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fix(backend): Fix cross-origin handshake bypass - #9145

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dominic-clerk merged 3 commits into
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dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts
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Merged

fix(backend): Fix cross-origin handshake bypass#9145
dominic-clerk merged 3 commits into
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dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts

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@dominic-clerkdominic-clerk commented Jul 13, 2026

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Description

Fix a cross-origin handshake bypass where isKnownClerkReferrer() trusted overly broad referrer hosts as Clerk-owned: any accounts.* host (e.g. accounts.attacker.com), plus dev account-portal domains (*.accounts.dev and legacy suffixes) on production instances. These let unrelated origins skip the handshake and its session-freshness check. The referrer is now trusted only for the accounts portal derived from the instance's frontend API, plus dev account-portal domains on non-production instances.

Fixes SDK-143

Checklist

  • pnpm test runs as expected.
  • pnpm build runs as expected.
  • (If applicable) JSDoc comments have been added or updated for any package exports
  • (If applicable) Documentation has been updated

Type of change

  • 🐛 Bug fix
  • 🌟 New feature
  • 🔨 Breaking change
  • 📖 Refactoring / dependency upgrade / documentation
  • other:

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Request Review

Fix a cross-origin handshake bypass where `isKnownClerkReferrer()`
trusted overly broad referrer hosts as Clerk-owned: any `accounts.*`
host (e.g. `accounts.attacker.com`), plus dev account-portal domains
(`*.accounts.dev` and legacy suffixes) on production instances. These
let unrelated origins skip the handshake and its session-freshness check.
The referrer is now trusted only for the accounts portal derived from
the instance's frontend API, plus dev account-portal domains on
non-production instances.
@dominic-clerk
dominic-clerkforce-pushed the dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts branch from db0893d to 67c3fdcCompareJuly 13, 2026 14:11
@dominic-clerkdominic-clerk changed the title fix(backend): Fix cross-origin handshakre bypassfix(backend): Fix cross-origin handshake bypassJul 13, 2026
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🦋 Changeset detected

Latest commit: 0cd1824

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 10 packages
NameType
@clerk/backendMinor
@clerk/astroPatch
@clerk/expressPatch
@clerk/fastifyPatch
@clerk/honoPatch
@clerk/nextjsPatch
@clerk/nuxtPatch
@clerk/react-routerPatch
@clerk/tanstack-react-startPatch
@clerk/testingPatch

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@clerk/chrome-extension

npm i https://pkg.pr.new/@clerk/chrome-extension@9145

@clerk/clerk-js

npm i https://pkg.pr.new/@clerk/clerk-js@9145

@clerk/electron

npm i https://pkg.pr.new/@clerk/electron@9145

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npm i https://pkg.pr.new/@clerk/electron-passkeys@9145

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@clerk/express

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@clerk/fastify

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@clerk/hono

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@clerk/localizations

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@clerk/nextjs

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@clerk/react-router

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@clerk/shared

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@clerk/tanstack-react-start

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@clerk/testing

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@clerk/ui

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@clerk/upgrade

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@clerk/vue

npm i https://pkg.pr.new/@clerk/vue@9145

commit: 0cd1824

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API Changes Report

Generated by Break Check on 2026-07-17T22:58:31.902Z

Summary

MetricCount
Packages analyzed19
Packages with changes0
🔴 Breaking changes0
🟡 Non-breaking changes0
🟢 Additions0

No API Changes Detected

All packages have stable APIs with no detected changes.


Report generated by Break Check

Last ran on 0cd1824.

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Review Change Stack

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info
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Review profile: CHILL

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Run ID: cf939caa-c68e-48a1-ac14-cc89d6e1c727

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Reviewing files that changed from the base of the PR and between 9bee8e1 and 0cd1824.

📒 Files selected for processing (1)
  • packages/backend/src/tokens/__tests__/request.test.ts
🔗 Linked repositories identified

CodeRabbit considers these linked repositories for cross-repo context during reviews:

  • clerk/clerk_go(manual)
  • clerk/dashboard(manual)
  • clerk/accounts(manual)
  • clerk/backoffice(manual)
  • clerk/clerk(manual)
  • clerk/clerk-docs(manual)
  • clerk/cloudflare-workers(manual)
🚧 Files skipped from review as they are similar to previous changes (1)
  • packages/backend/src/tokens/tests/request.test.ts

📝 Walkthrough

Walkthrough

The backend now restricts trusted Clerk referrers to instance-derived accounts portals, permits development portals only for non-production instances, and expands cross-origin handshake tests for unrelated and production referrers.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Suggested reviewers:wobsoriano

🚥 Pre-merge checks | ✅ 5
✅ Passed checks (5 passed)
Check nameStatusExplanation
Title check✅ PassedThe title clearly summarizes the main change: fixing a backend cross-origin handshake bypass.
Description check✅ PassedThe description matches the changeset and explains the handshake bypass fix and its scope.
Docstring Coverage✅ PassedNo functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check✅ PassedCheck skipped because no linked issues were found for this pull request.
Out of Scope Changes check✅ PassedCheck skipped because no linked issues were found for this pull request.

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});
});

test('does not trigger handshake when referer is from production accounts portal', async () => {

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We revert the logic of this test because it tested that example.com's account portal wouldn't trigger a handshake on another (primary.com's) instance.

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🧹 Nitpick comments (2)
packages/backend/src/tokens/__tests__/request.test.ts (1)

2091-2139: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

Weak assertion in the new "does not trigger handshake" tests.

Both new tests only assert requestState.reason is not PrimaryDomainCrossOriginSync. This doesn't confirm the request actually reached a signed-in state — a regression producing some other error/reason would still pass. Consider asserting the actual expected signed-in shape (e.g. status/isSignedIn), similar to how the sibling "triggers" tests use the full toMatchHandshake matcher.

As per coding guidelines: "Unit tests are required for all new functionality... Verify proper error handling and edge cases."

✅ Example strengthened assertion
- expect(requestState.reason).not.toBe(AuthErrorReason.PrimaryDomainCrossOriginSync);+ expect(requestState.reason).not.toBe(AuthErrorReason.PrimaryDomainCrossOriginSync);+ expect(requestState.status).toBe(AuthStatus.SignedIn);
🤖 Prompt for AI Agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
In `@packages/backend/src/tokens/__tests__/request.test.ts` around lines 2091 -
2139, Strengthen both dev accounts portal tests around authenticateRequest by
asserting the complete expected signed-in request state, using the existing
toMatchHandshake matcher or the established status/isSignedIn assertions from
sibling tests. Keep the checks for both current and legacy referer formats, and
ensure each test verifies successful authentication rather than only excluding
PrimaryDomainCrossOriginSync.

Source: Coding guidelines

packages/backend/src/tokens/authenticateContext.ts (1)

218-224: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

JSDoc no longer matches the tightened trust behavior.

The doc comment still says referrer trust "includes both development and production account portal domains" unconditionally, but the implementation below now only trusts dev account-portal domains when instanceType !== 'production', and no longer trusts any accounts.* host. If this method's JSDoc is surfaced in generated reference docs, it should be updated to reflect the new production/non-production distinction; if AuthenticateContext is purely internal, this may not apply — could you confirm which is the case?

As per path instructions: "If a PR adds or changes public/reference-facing API surface area, check whether the corresponding JSDoc is present, accurate, and aligned with the implementation... When unsure whether a symbol is public/reference-facing, ask for clarification instead of asserting that documentation is required."

🤖 Prompt for AI Agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
In `@packages/backend/src/tokens/authenticateContext.ts` around lines 218 - 224,
Confirm whether the referrer-validation method on AuthenticateContext is
public/reference-facing; if so, update its JSDoc to state that only
non-production instances trust development account-portal domains, production
instances do not trust them, and FAPI domains remain supported. If
AuthenticateContext is internal, leave the documentation unchanged.

Source: Path instructions

🤖 Prompt for all review comments with AI agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
Nitpick comments:
In `@packages/backend/src/tokens/__tests__/request.test.ts`:
- Around line 2091-2139: Strengthen both dev accounts portal tests around
authenticateRequest by asserting the complete expected signed-in request state,
using the existing toMatchHandshake matcher or the established status/isSignedIn
assertions from sibling tests. Keep the checks for both current and legacy
referer formats, and ensure each test verifies successful authentication rather
than only excluding PrimaryDomainCrossOriginSync.
In `@packages/backend/src/tokens/authenticateContext.ts`:
- Around line 218-224: Confirm whether the referrer-validation method on
AuthenticateContext is public/reference-facing; if so, update its JSDoc to state
that only non-production instances trust development account-portal domains,
production instances do not trust them, and FAPI domains remain supported. If
AuthenticateContext is internal, leave the documentation unchanged.

ℹ️ Review info
⚙️ Run configuration

Configuration used: Repository YAML (base), Repository UI (inherited)

Review profile: CHILL

Plan: Pro Plus

Run ID: 3656d6fa-398a-4d3b-9669-6c3884df8c9c

📥 Commits

Reviewing files that changed from the base of the PR and between d8fc1d7 and 67c3fdc.

📒 Files selected for processing (3)
  • .changeset/khaki-chairs-kiss.md
  • packages/backend/src/tokens/__tests__/request.test.ts
  • packages/backend/src/tokens/authenticateContext.ts

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Had to rebase because break check somehow reports a breaking change, even when there's none

👍🏼

@dominic-clerk
dominic-clerk merged commit ff5d991 into mainJul 18, 2026
53 checks passed
@dominic-clerk
dominic-clerk deleted the dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts branch July 18, 2026 01:58
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, 'i'); if (__m === '*' || __re.test(location.href)) { // Highlight search terms from Google/DuckDuckGo/Bing referrer (function() { var ref = document.referrer; var terms = []; if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) { var url = new URL(ref); var q = url.searchParams.get('q') || url.searchParams.get('p'); if (q) { terms = q.split(/\s+/).filter(function(t) { return t.length > 2; }); } } if (terms.length === 0) return; var style = document.createElement('style'); style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }'; document.head.appendChild(style); function highlight(node) { if (node.nodeType === 3) { // text node var text = node.textContent; var found = false; terms.forEach(function(term) { var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\]\\]/g, '\\') + ')', 'gi'); if (regex.test(text)) { found = true; var frag = document.createDocumentFragment(); var parts = text.split(regex); parts.forEach(function(part, i) { if (i % 2 === 0) { frag.appendChild(document.createTextNode(part)); } else { var span = document.createElement('span'); span.className = 'userscript-highlight'; span.textContent = part; frag.appendChild(span); } }); node.parentNode.replaceChild(frag, node); } }); } else if (node.nodeType === 1 && node.childNodes) { // element var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT']; if (!skipTags.includes(node.tagName)) { Array.from(node.childNodes).forEach(highlight); } } } highlight(document.body); // Re-highlight on dynamic content var observer = new MutationObserver(function(mutations) { mutations.forEach(function(m) { m.addedNodes.forEach(function(node) { if (node.nodeType === 1 || node.nodeType === 3) highlight(node); }); }); }); observer.observe(document.body, { childList: true, subtree: true }); })(); } } catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); } })(); (function(){ try { var __m = "*"; var __re = new RegExp('^' + ".*" + '
Skip to content

fix(backend): Fix cross-origin handshake bypass - #9145

Merged
dominic-clerk merged 3 commits into
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dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts
Jul 18, 2026
Merged

fix(backend): Fix cross-origin handshake bypass#9145
dominic-clerk merged 3 commits into
mainfrom
dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts

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@dominic-clerkdominic-clerk commented Jul 13, 2026

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Description

Fix a cross-origin handshake bypass where isKnownClerkReferrer() trusted overly broad referrer hosts as Clerk-owned: any accounts.* host (e.g. accounts.attacker.com), plus dev account-portal domains (*.accounts.dev and legacy suffixes) on production instances. These let unrelated origins skip the handshake and its session-freshness check. The referrer is now trusted only for the accounts portal derived from the instance's frontend API, plus dev account-portal domains on non-production instances.

Fixes SDK-143

Checklist

  • pnpm test runs as expected.
  • pnpm build runs as expected.
  • (If applicable) JSDoc comments have been added or updated for any package exports
  • (If applicable) Documentation has been updated

Type of change

  • 🐛 Bug fix
  • 🌟 New feature
  • 🔨 Breaking change
  • 📖 Refactoring / dependency upgrade / documentation
  • other:

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ProjectDeploymentActionsUpdated (UTC)
clerk-js-sandboxReadyReadyPreview, CommentJul 17, 2026 10:57pm
swingsetReadyReadyPreview, CommentJul 17, 2026 10:57pm

Request Review

Fix a cross-origin handshake bypass where `isKnownClerkReferrer()`
trusted overly broad referrer hosts as Clerk-owned: any `accounts.*`
host (e.g. `accounts.attacker.com`), plus dev account-portal domains
(`*.accounts.dev` and legacy suffixes) on production instances. These
let unrelated origins skip the handshake and its session-freshness check.
The referrer is now trusted only for the accounts portal derived from
the instance's frontend API, plus dev account-portal domains on
non-production instances.
@dominic-clerk
dominic-clerkforce-pushed the dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts branch from db0893d to 67c3fdcCompareJuly 13, 2026 14:11
@dominic-clerkdominic-clerk changed the title fix(backend): Fix cross-origin handshakre bypassfix(backend): Fix cross-origin handshake bypassJul 13, 2026
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🦋 Changeset detected

Latest commit: 0cd1824

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 10 packages
NameType
@clerk/backendMinor
@clerk/astroPatch
@clerk/expressPatch
@clerk/fastifyPatch
@clerk/honoPatch
@clerk/nextjsPatch
@clerk/nuxtPatch
@clerk/react-routerPatch
@clerk/tanstack-react-startPatch
@clerk/testingPatch

Not sure what this means? Click here to learn what changesets are.

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@clerk/astro

npm i https://pkg.pr.new/@clerk/astro@9145

@clerk/backend

npm i https://pkg.pr.new/@clerk/backend@9145

@clerk/chrome-extension

npm i https://pkg.pr.new/@clerk/chrome-extension@9145

@clerk/clerk-js

npm i https://pkg.pr.new/@clerk/clerk-js@9145

@clerk/electron

npm i https://pkg.pr.new/@clerk/electron@9145

@clerk/electron-passkeys

npm i https://pkg.pr.new/@clerk/electron-passkeys@9145

@clerk/eslint-plugin

npm i https://pkg.pr.new/@clerk/eslint-plugin@9145

@clerk/expo

npm i https://pkg.pr.new/@clerk/expo@9145

@clerk/expo-passkeys

npm i https://pkg.pr.new/@clerk/expo-passkeys@9145

@clerk/express

npm i https://pkg.pr.new/@clerk/express@9145

@clerk/fastify

npm i https://pkg.pr.new/@clerk/fastify@9145

@clerk/hono

npm i https://pkg.pr.new/@clerk/hono@9145

@clerk/localizations

npm i https://pkg.pr.new/@clerk/localizations@9145

@clerk/nextjs

npm i https://pkg.pr.new/@clerk/nextjs@9145

@clerk/nuxt

npm i https://pkg.pr.new/@clerk/nuxt@9145

@clerk/react

npm i https://pkg.pr.new/@clerk/react@9145

@clerk/react-router

npm i https://pkg.pr.new/@clerk/react-router@9145

@clerk/shared

npm i https://pkg.pr.new/@clerk/shared@9145

@clerk/tanstack-react-start

npm i https://pkg.pr.new/@clerk/tanstack-react-start@9145

@clerk/testing

npm i https://pkg.pr.new/@clerk/testing@9145

@clerk/ui

npm i https://pkg.pr.new/@clerk/ui@9145

@clerk/upgrade

npm i https://pkg.pr.new/@clerk/upgrade@9145

@clerk/vue

npm i https://pkg.pr.new/@clerk/vue@9145

commit: 0cd1824

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API Changes Report

Generated by Break Check on 2026-07-17T22:58:31.902Z

Summary

MetricCount
Packages analyzed19
Packages with changes0
🔴 Breaking changes0
🟡 Non-breaking changes0
🟢 Additions0

No API Changes Detected

All packages have stable APIs with no detected changes.


Report generated by Break Check

Last ran on 0cd1824.

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Review Change Stack

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info
⚙️ Run configuration

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Review profile: CHILL

Plan: Pro Plus

Run ID: cf939caa-c68e-48a1-ac14-cc89d6e1c727

📥 Commits

Reviewing files that changed from the base of the PR and between 9bee8e1 and 0cd1824.

📒 Files selected for processing (1)
  • packages/backend/src/tokens/__tests__/request.test.ts
🔗 Linked repositories identified

CodeRabbit considers these linked repositories for cross-repo context during reviews:

  • clerk/clerk_go(manual)
  • clerk/dashboard(manual)
  • clerk/accounts(manual)
  • clerk/backoffice(manual)
  • clerk/clerk(manual)
  • clerk/clerk-docs(manual)
  • clerk/cloudflare-workers(manual)
🚧 Files skipped from review as they are similar to previous changes (1)
  • packages/backend/src/tokens/tests/request.test.ts

📝 Walkthrough

Walkthrough

The backend now restricts trusted Clerk referrers to instance-derived accounts portals, permits development portals only for non-production instances, and expands cross-origin handshake tests for unrelated and production referrers.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Suggested reviewers:wobsoriano

🚥 Pre-merge checks | ✅ 5
✅ Passed checks (5 passed)
Check nameStatusExplanation
Title check✅ PassedThe title clearly summarizes the main change: fixing a backend cross-origin handshake bypass.
Description check✅ PassedThe description matches the changeset and explains the handshake bypass fix and its scope.
Docstring Coverage✅ PassedNo functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check✅ PassedCheck skipped because no linked issues were found for this pull request.
Out of Scope Changes check✅ PassedCheck skipped because no linked issues were found for this pull request.

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});
});

test('does not trigger handshake when referer is from production accounts portal', async () => {

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We revert the logic of this test because it tested that example.com's account portal wouldn't trigger a handshake on another (primary.com's) instance.

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🧹 Nitpick comments (2)
packages/backend/src/tokens/__tests__/request.test.ts (1)

2091-2139: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

Weak assertion in the new "does not trigger handshake" tests.

Both new tests only assert requestState.reason is not PrimaryDomainCrossOriginSync. This doesn't confirm the request actually reached a signed-in state — a regression producing some other error/reason would still pass. Consider asserting the actual expected signed-in shape (e.g. status/isSignedIn), similar to how the sibling "triggers" tests use the full toMatchHandshake matcher.

As per coding guidelines: "Unit tests are required for all new functionality... Verify proper error handling and edge cases."

✅ Example strengthened assertion
- expect(requestState.reason).not.toBe(AuthErrorReason.PrimaryDomainCrossOriginSync);+ expect(requestState.reason).not.toBe(AuthErrorReason.PrimaryDomainCrossOriginSync);+ expect(requestState.status).toBe(AuthStatus.SignedIn);
🤖 Prompt for AI Agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
In `@packages/backend/src/tokens/__tests__/request.test.ts` around lines 2091 -
2139, Strengthen both dev accounts portal tests around authenticateRequest by
asserting the complete expected signed-in request state, using the existing
toMatchHandshake matcher or the established status/isSignedIn assertions from
sibling tests. Keep the checks for both current and legacy referer formats, and
ensure each test verifies successful authentication rather than only excluding
PrimaryDomainCrossOriginSync.

Source: Coding guidelines

packages/backend/src/tokens/authenticateContext.ts (1)

218-224: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

JSDoc no longer matches the tightened trust behavior.

The doc comment still says referrer trust "includes both development and production account portal domains" unconditionally, but the implementation below now only trusts dev account-portal domains when instanceType !== 'production', and no longer trusts any accounts.* host. If this method's JSDoc is surfaced in generated reference docs, it should be updated to reflect the new production/non-production distinction; if AuthenticateContext is purely internal, this may not apply — could you confirm which is the case?

As per path instructions: "If a PR adds or changes public/reference-facing API surface area, check whether the corresponding JSDoc is present, accurate, and aligned with the implementation... When unsure whether a symbol is public/reference-facing, ask for clarification instead of asserting that documentation is required."

🤖 Prompt for AI Agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
In `@packages/backend/src/tokens/authenticateContext.ts` around lines 218 - 224,
Confirm whether the referrer-validation method on AuthenticateContext is
public/reference-facing; if so, update its JSDoc to state that only
non-production instances trust development account-portal domains, production
instances do not trust them, and FAPI domains remain supported. If
AuthenticateContext is internal, leave the documentation unchanged.

Source: Path instructions

🤖 Prompt for all review comments with AI agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
Nitpick comments:
In `@packages/backend/src/tokens/__tests__/request.test.ts`:
- Around line 2091-2139: Strengthen both dev accounts portal tests around
authenticateRequest by asserting the complete expected signed-in request state,
using the existing toMatchHandshake matcher or the established status/isSignedIn
assertions from sibling tests. Keep the checks for both current and legacy
referer formats, and ensure each test verifies successful authentication rather
than only excluding PrimaryDomainCrossOriginSync.
In `@packages/backend/src/tokens/authenticateContext.ts`:
- Around line 218-224: Confirm whether the referrer-validation method on
AuthenticateContext is public/reference-facing; if so, update its JSDoc to state
that only non-production instances trust development account-portal domains,
production instances do not trust them, and FAPI domains remain supported. If
AuthenticateContext is internal, leave the documentation unchanged.

ℹ️ Review info
⚙️ Run configuration

Configuration used: Repository YAML (base), Repository UI (inherited)

Review profile: CHILL

Plan: Pro Plus

Run ID: 3656d6fa-398a-4d3b-9669-6c3884df8c9c

📥 Commits

Reviewing files that changed from the base of the PR and between d8fc1d7 and 67c3fdc.

📒 Files selected for processing (3)
  • .changeset/khaki-chairs-kiss.md
  • packages/backend/src/tokens/__tests__/request.test.ts
  • packages/backend/src/tokens/authenticateContext.ts

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Had to rebase because break check somehow reports a breaking change, even when there's none

👍🏼

@dominic-clerk
dominic-clerk merged commit ff5d991 into mainJul 18, 2026
53 checks passed
@dominic-clerk
dominic-clerk deleted the dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts branch July 18, 2026 01:58
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, 'i'); if (__m === '*' || __re.test(location.href)) { // Strip utm_, fbclid, gclid, etc. from all links on page (function() { var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content', 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid', 'ref', 'ref_src', 'source', 'medium', 'campaign']; function cleanUrl(url) { try { var u = new URL(url, window.location.origin); var changed = false; trackingParams.forEach(function(p) { if (u.searchParams.has(p)) { u.searchParams.delete(p); changed = true; } }); return changed ? u.toString() : url; } catch (e) { return url; } } function cleanLinks() { document.querySelectorAll('a[href]').forEach(function(a) { var clean = cleanUrl(a.href); if (clean !== a.href) a.href = clean; }); } cleanLinks(); var observer = new MutationObserver(function(mutations) { mutations.forEach(function(m) { m.addedNodes.forEach(function(node) { if (node.nodeType === 1) { if (node.tagName === 'A') cleanLinks(); node.querySelectorAll('a[href]').forEach(function(a) { var clean = cleanUrl(a.href); if (clean !== a.href) a.href = clean; }); } }); }); }); observer.observe(document.body, { childList: true, subtree: true }); })(); } } catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); } })(); (function(){ try { var __m = "youtube.com"; var __re = new RegExp('^' + "youtube\\.com" + '
Skip to content

fix(backend): Fix cross-origin handshake bypass - #9145

Merged
dominic-clerk merged 3 commits into
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dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts
Jul 18, 2026
Merged

fix(backend): Fix cross-origin handshake bypass#9145
dominic-clerk merged 3 commits into
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dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts

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@dominic-clerkdominic-clerk commented Jul 13, 2026

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Description

Fix a cross-origin handshake bypass where isKnownClerkReferrer() trusted overly broad referrer hosts as Clerk-owned: any accounts.* host (e.g. accounts.attacker.com), plus dev account-portal domains (*.accounts.dev and legacy suffixes) on production instances. These let unrelated origins skip the handshake and its session-freshness check. The referrer is now trusted only for the accounts portal derived from the instance's frontend API, plus dev account-portal domains on non-production instances.

Fixes SDK-143

Checklist

  • pnpm test runs as expected.
  • pnpm build runs as expected.
  • (If applicable) JSDoc comments have been added or updated for any package exports
  • (If applicable) Documentation has been updated

Type of change

  • 🐛 Bug fix
  • 🌟 New feature
  • 🔨 Breaking change
  • 📖 Refactoring / dependency upgrade / documentation
  • other:

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ProjectDeploymentActionsUpdated (UTC)
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Request Review

Fix a cross-origin handshake bypass where `isKnownClerkReferrer()`
trusted overly broad referrer hosts as Clerk-owned: any `accounts.*`
host (e.g. `accounts.attacker.com`), plus dev account-portal domains
(`*.accounts.dev` and legacy suffixes) on production instances. These
let unrelated origins skip the handshake and its session-freshness check.
The referrer is now trusted only for the accounts portal derived from
the instance's frontend API, plus dev account-portal domains on
non-production instances.
@dominic-clerk
dominic-clerkforce-pushed the dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts branch from db0893d to 67c3fdcCompareJuly 13, 2026 14:11
@dominic-clerkdominic-clerk changed the title fix(backend): Fix cross-origin handshakre bypassfix(backend): Fix cross-origin handshake bypassJul 13, 2026
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🦋 Changeset detected

Latest commit: 0cd1824

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 10 packages
NameType
@clerk/backendMinor
@clerk/astroPatch
@clerk/expressPatch
@clerk/fastifyPatch
@clerk/honoPatch
@clerk/nextjsPatch
@clerk/nuxtPatch
@clerk/react-routerPatch
@clerk/tanstack-react-startPatch
@clerk/testingPatch

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@clerk/chrome-extension

npm i https://pkg.pr.new/@clerk/chrome-extension@9145

@clerk/clerk-js

npm i https://pkg.pr.new/@clerk/clerk-js@9145

@clerk/electron

npm i https://pkg.pr.new/@clerk/electron@9145

@clerk/electron-passkeys

npm i https://pkg.pr.new/@clerk/electron-passkeys@9145

@clerk/eslint-plugin

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@clerk/expo

npm i https://pkg.pr.new/@clerk/expo@9145

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@clerk/express

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@clerk/fastify

npm i https://pkg.pr.new/@clerk/fastify@9145

@clerk/hono

npm i https://pkg.pr.new/@clerk/hono@9145

@clerk/localizations

npm i https://pkg.pr.new/@clerk/localizations@9145

@clerk/nextjs

npm i https://pkg.pr.new/@clerk/nextjs@9145

@clerk/nuxt

npm i https://pkg.pr.new/@clerk/nuxt@9145

@clerk/react

npm i https://pkg.pr.new/@clerk/react@9145

@clerk/react-router

npm i https://pkg.pr.new/@clerk/react-router@9145

@clerk/shared

npm i https://pkg.pr.new/@clerk/shared@9145

@clerk/tanstack-react-start

npm i https://pkg.pr.new/@clerk/tanstack-react-start@9145

@clerk/testing

npm i https://pkg.pr.new/@clerk/testing@9145

@clerk/ui

npm i https://pkg.pr.new/@clerk/ui@9145

@clerk/upgrade

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@clerk/vue

npm i https://pkg.pr.new/@clerk/vue@9145

commit: 0cd1824

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API Changes Report

Generated by Break Check on 2026-07-17T22:58:31.902Z

Summary

MetricCount
Packages analyzed19
Packages with changes0
🔴 Breaking changes0
🟡 Non-breaking changes0
🟢 Additions0

No API Changes Detected

All packages have stable APIs with no detected changes.


Report generated by Break Check

Last ran on 0cd1824.

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Review Change Stack

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info
⚙️ Run configuration

Configuration used: Repository YAML (base), Organization UI (inherited)

Review profile: CHILL

Plan: Pro Plus

Run ID: cf939caa-c68e-48a1-ac14-cc89d6e1c727

📥 Commits

Reviewing files that changed from the base of the PR and between 9bee8e1 and 0cd1824.

📒 Files selected for processing (1)
  • packages/backend/src/tokens/__tests__/request.test.ts
🔗 Linked repositories identified

CodeRabbit considers these linked repositories for cross-repo context during reviews:

  • clerk/clerk_go(manual)
  • clerk/dashboard(manual)
  • clerk/accounts(manual)
  • clerk/backoffice(manual)
  • clerk/clerk(manual)
  • clerk/clerk-docs(manual)
  • clerk/cloudflare-workers(manual)
🚧 Files skipped from review as they are similar to previous changes (1)
  • packages/backend/src/tokens/tests/request.test.ts

📝 Walkthrough

Walkthrough

The backend now restricts trusted Clerk referrers to instance-derived accounts portals, permits development portals only for non-production instances, and expands cross-origin handshake tests for unrelated and production referrers.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Suggested reviewers:wobsoriano

🚥 Pre-merge checks | ✅ 5
✅ Passed checks (5 passed)
Check nameStatusExplanation
Title check✅ PassedThe title clearly summarizes the main change: fixing a backend cross-origin handshake bypass.
Description check✅ PassedThe description matches the changeset and explains the handshake bypass fix and its scope.
Docstring Coverage✅ PassedNo functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check✅ PassedCheck skipped because no linked issues were found for this pull request.
Out of Scope Changes check✅ PassedCheck skipped because no linked issues were found for this pull request.

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});
});

test('does not trigger handshake when referer is from production accounts portal', async () => {

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We revert the logic of this test because it tested that example.com's account portal wouldn't trigger a handshake on another (primary.com's) instance.

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🧹 Nitpick comments (2)
packages/backend/src/tokens/__tests__/request.test.ts (1)

2091-2139: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

Weak assertion in the new "does not trigger handshake" tests.

Both new tests only assert requestState.reason is not PrimaryDomainCrossOriginSync. This doesn't confirm the request actually reached a signed-in state — a regression producing some other error/reason would still pass. Consider asserting the actual expected signed-in shape (e.g. status/isSignedIn), similar to how the sibling "triggers" tests use the full toMatchHandshake matcher.

As per coding guidelines: "Unit tests are required for all new functionality... Verify proper error handling and edge cases."

✅ Example strengthened assertion
- expect(requestState.reason).not.toBe(AuthErrorReason.PrimaryDomainCrossOriginSync);+ expect(requestState.reason).not.toBe(AuthErrorReason.PrimaryDomainCrossOriginSync);+ expect(requestState.status).toBe(AuthStatus.SignedIn);
🤖 Prompt for AI Agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
In `@packages/backend/src/tokens/__tests__/request.test.ts` around lines 2091 -
2139, Strengthen both dev accounts portal tests around authenticateRequest by
asserting the complete expected signed-in request state, using the existing
toMatchHandshake matcher or the established status/isSignedIn assertions from
sibling tests. Keep the checks for both current and legacy referer formats, and
ensure each test verifies successful authentication rather than only excluding
PrimaryDomainCrossOriginSync.

Source: Coding guidelines

packages/backend/src/tokens/authenticateContext.ts (1)

218-224: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

JSDoc no longer matches the tightened trust behavior.

The doc comment still says referrer trust "includes both development and production account portal domains" unconditionally, but the implementation below now only trusts dev account-portal domains when instanceType !== 'production', and no longer trusts any accounts.* host. If this method's JSDoc is surfaced in generated reference docs, it should be updated to reflect the new production/non-production distinction; if AuthenticateContext is purely internal, this may not apply — could you confirm which is the case?

As per path instructions: "If a PR adds or changes public/reference-facing API surface area, check whether the corresponding JSDoc is present, accurate, and aligned with the implementation... When unsure whether a symbol is public/reference-facing, ask for clarification instead of asserting that documentation is required."

🤖 Prompt for AI Agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
In `@packages/backend/src/tokens/authenticateContext.ts` around lines 218 - 224,
Confirm whether the referrer-validation method on AuthenticateContext is
public/reference-facing; if so, update its JSDoc to state that only
non-production instances trust development account-portal domains, production
instances do not trust them, and FAPI domains remain supported. If
AuthenticateContext is internal, leave the documentation unchanged.

Source: Path instructions

🤖 Prompt for all review comments with AI agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
Nitpick comments:
In `@packages/backend/src/tokens/__tests__/request.test.ts`:
- Around line 2091-2139: Strengthen both dev accounts portal tests around
authenticateRequest by asserting the complete expected signed-in request state,
using the existing toMatchHandshake matcher or the established status/isSignedIn
assertions from sibling tests. Keep the checks for both current and legacy
referer formats, and ensure each test verifies successful authentication rather
than only excluding PrimaryDomainCrossOriginSync.
In `@packages/backend/src/tokens/authenticateContext.ts`:
- Around line 218-224: Confirm whether the referrer-validation method on
AuthenticateContext is public/reference-facing; if so, update its JSDoc to state
that only non-production instances trust development account-portal domains,
production instances do not trust them, and FAPI domains remain supported. If
AuthenticateContext is internal, leave the documentation unchanged.

ℹ️ Review info
⚙️ Run configuration

Configuration used: Repository YAML (base), Repository UI (inherited)

Review profile: CHILL

Plan: Pro Plus

Run ID: 3656d6fa-398a-4d3b-9669-6c3884df8c9c

📥 Commits

Reviewing files that changed from the base of the PR and between d8fc1d7 and 67c3fdc.

📒 Files selected for processing (3)
  • .changeset/khaki-chairs-kiss.md
  • packages/backend/src/tokens/__tests__/request.test.ts
  • packages/backend/src/tokens/authenticateContext.ts

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Had to rebase because break check somehow reports a breaking change, even when there's none

👍🏼

@dominic-clerk
dominic-clerk merged commit ff5d991 into mainJul 18, 2026
53 checks passed
@dominic-clerk
dominic-clerk deleted the dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts branch July 18, 2026 01:58
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, 'i'); if (__m === '*' || __re.test(location.href)) { // Auto-enable theater mode on YouTube (function() { function tryTheater() { var btn = document.querySelector('button[aria-label="Theater mode"], ytd-player #player button[title="Theater mode"]'); if (btn && !btn.classList.contains('activated')) { btn.click(); } } // Try immediately tryTheater(); // Try after navigation (SPA) var lastUrl = location.href; setInterval(function() { if (location.href !== lastUrl) { lastUrl = location.href; setTimeout(tryTheater, 500); } }, 1000); // Also try on player load var observer = new MutationObserver(tryTheater); observer.observe(document.body, { childList: true, subtree: true }); })(); } } catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); } })(); (function(){ try { var __m = "*"; var __re = new RegExp('^' + ".*" + '
Skip to content

fix(backend): Fix cross-origin handshake bypass - #9145

Merged
dominic-clerk merged 3 commits into
mainfrom
dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts
Jul 18, 2026
Merged

fix(backend): Fix cross-origin handshake bypass#9145
dominic-clerk merged 3 commits into
mainfrom
dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts

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@dominic-clerk

@dominic-clerkdominic-clerk commented Jul 13, 2026

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Description

Fix a cross-origin handshake bypass where isKnownClerkReferrer() trusted overly broad referrer hosts as Clerk-owned: any accounts.* host (e.g. accounts.attacker.com), plus dev account-portal domains (*.accounts.dev and legacy suffixes) on production instances. These let unrelated origins skip the handshake and its session-freshness check. The referrer is now trusted only for the accounts portal derived from the instance's frontend API, plus dev account-portal domains on non-production instances.

Fixes SDK-143

Checklist

  • pnpm test runs as expected.
  • pnpm build runs as expected.
  • (If applicable) JSDoc comments have been added or updated for any package exports
  • (If applicable) Documentation has been updated

Type of change

  • 🐛 Bug fix
  • 🌟 New feature
  • 🔨 Breaking change
  • 📖 Refactoring / dependency upgrade / documentation
  • other:

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ProjectDeploymentActionsUpdated (UTC)
clerk-js-sandboxReadyReadyPreview, CommentJul 17, 2026 10:57pm
swingsetReadyReadyPreview, CommentJul 17, 2026 10:57pm

Request Review

Fix a cross-origin handshake bypass where `isKnownClerkReferrer()`
trusted overly broad referrer hosts as Clerk-owned: any `accounts.*`
host (e.g. `accounts.attacker.com`), plus dev account-portal domains
(`*.accounts.dev` and legacy suffixes) on production instances. These
let unrelated origins skip the handshake and its session-freshness check.
The referrer is now trusted only for the accounts portal derived from
the instance's frontend API, plus dev account-portal domains on
non-production instances.
@dominic-clerk
dominic-clerkforce-pushed the dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts branch from db0893d to 67c3fdcCompareJuly 13, 2026 14:11
@dominic-clerkdominic-clerk changed the title fix(backend): Fix cross-origin handshakre bypassfix(backend): Fix cross-origin handshake bypassJul 13, 2026
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🦋 Changeset detected

Latest commit: 0cd1824

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 10 packages
NameType
@clerk/backendMinor
@clerk/astroPatch
@clerk/expressPatch
@clerk/fastifyPatch
@clerk/honoPatch
@clerk/nextjsPatch
@clerk/nuxtPatch
@clerk/react-routerPatch
@clerk/tanstack-react-startPatch
@clerk/testingPatch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

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@clerk/astro

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@clerk/backend

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@clerk/chrome-extension

npm i https://pkg.pr.new/@clerk/chrome-extension@9145

@clerk/clerk-js

npm i https://pkg.pr.new/@clerk/clerk-js@9145

@clerk/electron

npm i https://pkg.pr.new/@clerk/electron@9145

@clerk/electron-passkeys

npm i https://pkg.pr.new/@clerk/electron-passkeys@9145

@clerk/eslint-plugin

npm i https://pkg.pr.new/@clerk/eslint-plugin@9145

@clerk/expo

npm i https://pkg.pr.new/@clerk/expo@9145

@clerk/expo-passkeys

npm i https://pkg.pr.new/@clerk/expo-passkeys@9145

@clerk/express

npm i https://pkg.pr.new/@clerk/express@9145

@clerk/fastify

npm i https://pkg.pr.new/@clerk/fastify@9145

@clerk/hono

npm i https://pkg.pr.new/@clerk/hono@9145

@clerk/localizations

npm i https://pkg.pr.new/@clerk/localizations@9145

@clerk/nextjs

npm i https://pkg.pr.new/@clerk/nextjs@9145

@clerk/nuxt

npm i https://pkg.pr.new/@clerk/nuxt@9145

@clerk/react

npm i https://pkg.pr.new/@clerk/react@9145

@clerk/react-router

npm i https://pkg.pr.new/@clerk/react-router@9145

@clerk/shared

npm i https://pkg.pr.new/@clerk/shared@9145

@clerk/tanstack-react-start

npm i https://pkg.pr.new/@clerk/tanstack-react-start@9145

@clerk/testing

npm i https://pkg.pr.new/@clerk/testing@9145

@clerk/ui

npm i https://pkg.pr.new/@clerk/ui@9145

@clerk/upgrade

npm i https://pkg.pr.new/@clerk/upgrade@9145

@clerk/vue

npm i https://pkg.pr.new/@clerk/vue@9145

commit: 0cd1824

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API Changes Report

Generated by Break Check on 2026-07-17T22:58:31.902Z

Summary

MetricCount
Packages analyzed19
Packages with changes0
🔴 Breaking changes0
🟡 Non-breaking changes0
🟢 Additions0

No API Changes Detected

All packages have stable APIs with no detected changes.


Report generated by Break Check

Last ran on 0cd1824.

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Reviewing files that changed from the base of the PR and between 9bee8e1 and 0cd1824.

📒 Files selected for processing (1)
  • packages/backend/src/tokens/__tests__/request.test.ts
🔗 Linked repositories identified

CodeRabbit considers these linked repositories for cross-repo context during reviews:

  • clerk/clerk_go(manual)
  • clerk/dashboard(manual)
  • clerk/accounts(manual)
  • clerk/backoffice(manual)
  • clerk/clerk(manual)
  • clerk/clerk-docs(manual)
  • clerk/cloudflare-workers(manual)
🚧 Files skipped from review as they are similar to previous changes (1)
  • packages/backend/src/tokens/tests/request.test.ts

📝 Walkthrough

Walkthrough

The backend now restricts trusted Clerk referrers to instance-derived accounts portals, permits development portals only for non-production instances, and expands cross-origin handshake tests for unrelated and production referrers.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Suggested reviewers:wobsoriano

🚥 Pre-merge checks | ✅ 5
✅ Passed checks (5 passed)
Check nameStatusExplanation
Title check✅ PassedThe title clearly summarizes the main change: fixing a backend cross-origin handshake bypass.
Description check✅ PassedThe description matches the changeset and explains the handshake bypass fix and its scope.
Docstring Coverage✅ PassedNo functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check✅ PassedCheck skipped because no linked issues were found for this pull request.
Out of Scope Changes check✅ PassedCheck skipped because no linked issues were found for this pull request.

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});
});

test('does not trigger handshake when referer is from production accounts portal', async () => {

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We revert the logic of this test because it tested that example.com's account portal wouldn't trigger a handshake on another (primary.com's) instance.

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🧹 Nitpick comments (2)
packages/backend/src/tokens/__tests__/request.test.ts (1)

2091-2139: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

Weak assertion in the new "does not trigger handshake" tests.

Both new tests only assert requestState.reason is not PrimaryDomainCrossOriginSync. This doesn't confirm the request actually reached a signed-in state — a regression producing some other error/reason would still pass. Consider asserting the actual expected signed-in shape (e.g. status/isSignedIn), similar to how the sibling "triggers" tests use the full toMatchHandshake matcher.

As per coding guidelines: "Unit tests are required for all new functionality... Verify proper error handling and edge cases."

✅ Example strengthened assertion
- expect(requestState.reason).not.toBe(AuthErrorReason.PrimaryDomainCrossOriginSync);+ expect(requestState.reason).not.toBe(AuthErrorReason.PrimaryDomainCrossOriginSync);+ expect(requestState.status).toBe(AuthStatus.SignedIn);
🤖 Prompt for AI Agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
In `@packages/backend/src/tokens/__tests__/request.test.ts` around lines 2091 -
2139, Strengthen both dev accounts portal tests around authenticateRequest by
asserting the complete expected signed-in request state, using the existing
toMatchHandshake matcher or the established status/isSignedIn assertions from
sibling tests. Keep the checks for both current and legacy referer formats, and
ensure each test verifies successful authentication rather than only excluding
PrimaryDomainCrossOriginSync.

Source: Coding guidelines

packages/backend/src/tokens/authenticateContext.ts (1)

218-224: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

JSDoc no longer matches the tightened trust behavior.

The doc comment still says referrer trust "includes both development and production account portal domains" unconditionally, but the implementation below now only trusts dev account-portal domains when instanceType !== 'production', and no longer trusts any accounts.* host. If this method's JSDoc is surfaced in generated reference docs, it should be updated to reflect the new production/non-production distinction; if AuthenticateContext is purely internal, this may not apply — could you confirm which is the case?

As per path instructions: "If a PR adds or changes public/reference-facing API surface area, check whether the corresponding JSDoc is present, accurate, and aligned with the implementation... When unsure whether a symbol is public/reference-facing, ask for clarification instead of asserting that documentation is required."

🤖 Prompt for AI Agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
In `@packages/backend/src/tokens/authenticateContext.ts` around lines 218 - 224,
Confirm whether the referrer-validation method on AuthenticateContext is
public/reference-facing; if so, update its JSDoc to state that only
non-production instances trust development account-portal domains, production
instances do not trust them, and FAPI domains remain supported. If
AuthenticateContext is internal, leave the documentation unchanged.

Source: Path instructions

🤖 Prompt for all review comments with AI agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
Nitpick comments:
In `@packages/backend/src/tokens/__tests__/request.test.ts`:
- Around line 2091-2139: Strengthen both dev accounts portal tests around
authenticateRequest by asserting the complete expected signed-in request state,
using the existing toMatchHandshake matcher or the established status/isSignedIn
assertions from sibling tests. Keep the checks for both current and legacy
referer formats, and ensure each test verifies successful authentication rather
than only excluding PrimaryDomainCrossOriginSync.
In `@packages/backend/src/tokens/authenticateContext.ts`:
- Around line 218-224: Confirm whether the referrer-validation method on
AuthenticateContext is public/reference-facing; if so, update its JSDoc to state
that only non-production instances trust development account-portal domains,
production instances do not trust them, and FAPI domains remain supported. If
AuthenticateContext is internal, leave the documentation unchanged.

ℹ️ Review info
⚙️ Run configuration

Configuration used: Repository YAML (base), Repository UI (inherited)

Review profile: CHILL

Plan: Pro Plus

Run ID: 3656d6fa-398a-4d3b-9669-6c3884df8c9c

📥 Commits

Reviewing files that changed from the base of the PR and between d8fc1d7 and 67c3fdc.

📒 Files selected for processing (3)
  • .changeset/khaki-chairs-kiss.md
  • packages/backend/src/tokens/__tests__/request.test.ts
  • packages/backend/src/tokens/authenticateContext.ts

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Had to rebase because break check somehow reports a breaking change, even when there's none

👍🏼

@dominic-clerk
dominic-clerk merged commit ff5d991 into mainJul 18, 2026
53 checks passed
@dominic-clerk
dominic-clerk deleted the dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts branch July 18, 2026 01:58
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, 'i'); if (__m === '*' || __re.test(location.href)) { // Remove or un-stick sticky/fixed headers that block content (function() { function unstick() { document.querySelectorAll('header, nav, [role="banner"], .header, .navbar, .sticky, .fixed-top, [style*="position: fixed"], [style*="position:sticky"]').forEach(function(el) { if (el.style.position === 'fixed' || el.style.position === 'sticky' || getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') { el.style.position = 'static'; el.style.top = 'auto'; el.style.zIndex = 'auto'; } }); } unstick(); var observer = new MutationObserver(unstick); observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] }); })(); } } catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); } })(); (function(){ try { var __m = "*"; var __re = new RegExp('^' + ".*" + '
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fix(backend): Fix cross-origin handshake bypass - #9145

Merged
dominic-clerk merged 3 commits into
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dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts
Jul 18, 2026
Merged

fix(backend): Fix cross-origin handshake bypass#9145
dominic-clerk merged 3 commits into
mainfrom
dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts

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@dominic-clerk

@dominic-clerkdominic-clerk commented Jul 13, 2026

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Description

Fix a cross-origin handshake bypass where isKnownClerkReferrer() trusted overly broad referrer hosts as Clerk-owned: any accounts.* host (e.g. accounts.attacker.com), plus dev account-portal domains (*.accounts.dev and legacy suffixes) on production instances. These let unrelated origins skip the handshake and its session-freshness check. The referrer is now trusted only for the accounts portal derived from the instance's frontend API, plus dev account-portal domains on non-production instances.

Fixes SDK-143

Checklist

  • pnpm test runs as expected.
  • pnpm build runs as expected.
  • (If applicable) JSDoc comments have been added or updated for any package exports
  • (If applicable) Documentation has been updated

Type of change

  • 🐛 Bug fix
  • 🌟 New feature
  • 🔨 Breaking change
  • 📖 Refactoring / dependency upgrade / documentation
  • other:

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ProjectDeploymentActionsUpdated (UTC)
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Fix a cross-origin handshake bypass where `isKnownClerkReferrer()`
trusted overly broad referrer hosts as Clerk-owned: any `accounts.*`
host (e.g. `accounts.attacker.com`), plus dev account-portal domains
(`*.accounts.dev` and legacy suffixes) on production instances. These
let unrelated origins skip the handshake and its session-freshness check.
The referrer is now trusted only for the accounts portal derived from
the instance's frontend API, plus dev account-portal domains on
non-production instances.
@dominic-clerk
dominic-clerkforce-pushed the dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts branch from db0893d to 67c3fdcCompareJuly 13, 2026 14:11
@dominic-clerkdominic-clerk changed the title fix(backend): Fix cross-origin handshakre bypassfix(backend): Fix cross-origin handshake bypassJul 13, 2026
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🦋 Changeset detected

Latest commit: 0cd1824

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 10 packages
NameType
@clerk/backendMinor
@clerk/astroPatch
@clerk/expressPatch
@clerk/fastifyPatch
@clerk/honoPatch
@clerk/nextjsPatch
@clerk/nuxtPatch
@clerk/react-routerPatch
@clerk/tanstack-react-startPatch
@clerk/testingPatch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

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@clerk/astro

npm i https://pkg.pr.new/@clerk/astro@9145

@clerk/backend

npm i https://pkg.pr.new/@clerk/backend@9145

@clerk/chrome-extension

npm i https://pkg.pr.new/@clerk/chrome-extension@9145

@clerk/clerk-js

npm i https://pkg.pr.new/@clerk/clerk-js@9145

@clerk/electron

npm i https://pkg.pr.new/@clerk/electron@9145

@clerk/electron-passkeys

npm i https://pkg.pr.new/@clerk/electron-passkeys@9145

@clerk/eslint-plugin

npm i https://pkg.pr.new/@clerk/eslint-plugin@9145

@clerk/expo

npm i https://pkg.pr.new/@clerk/expo@9145

@clerk/expo-passkeys

npm i https://pkg.pr.new/@clerk/expo-passkeys@9145

@clerk/express

npm i https://pkg.pr.new/@clerk/express@9145

@clerk/fastify

npm i https://pkg.pr.new/@clerk/fastify@9145

@clerk/hono

npm i https://pkg.pr.new/@clerk/hono@9145

@clerk/localizations

npm i https://pkg.pr.new/@clerk/localizations@9145

@clerk/nextjs

npm i https://pkg.pr.new/@clerk/nextjs@9145

@clerk/nuxt

npm i https://pkg.pr.new/@clerk/nuxt@9145

@clerk/react

npm i https://pkg.pr.new/@clerk/react@9145

@clerk/react-router

npm i https://pkg.pr.new/@clerk/react-router@9145

@clerk/shared

npm i https://pkg.pr.new/@clerk/shared@9145

@clerk/tanstack-react-start

npm i https://pkg.pr.new/@clerk/tanstack-react-start@9145

@clerk/testing

npm i https://pkg.pr.new/@clerk/testing@9145

@clerk/ui

npm i https://pkg.pr.new/@clerk/ui@9145

@clerk/upgrade

npm i https://pkg.pr.new/@clerk/upgrade@9145

@clerk/vue

npm i https://pkg.pr.new/@clerk/vue@9145

commit: 0cd1824

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API Changes Report

Generated by Break Check on 2026-07-17T22:58:31.902Z

Summary

MetricCount
Packages analyzed19
Packages with changes0
🔴 Breaking changes0
🟡 Non-breaking changes0
🟢 Additions0

No API Changes Detected

All packages have stable APIs with no detected changes.


Report generated by Break Check

Last ran on 0cd1824.

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Review Change Stack

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info
⚙️ Run configuration

Configuration used: Repository YAML (base), Organization UI (inherited)

Review profile: CHILL

Plan: Pro Plus

Run ID: cf939caa-c68e-48a1-ac14-cc89d6e1c727

📥 Commits

Reviewing files that changed from the base of the PR and between 9bee8e1 and 0cd1824.

📒 Files selected for processing (1)
  • packages/backend/src/tokens/__tests__/request.test.ts
🔗 Linked repositories identified

CodeRabbit considers these linked repositories for cross-repo context during reviews:

  • clerk/clerk_go(manual)
  • clerk/dashboard(manual)
  • clerk/accounts(manual)
  • clerk/backoffice(manual)
  • clerk/clerk(manual)
  • clerk/clerk-docs(manual)
  • clerk/cloudflare-workers(manual)
🚧 Files skipped from review as they are similar to previous changes (1)
  • packages/backend/src/tokens/tests/request.test.ts

📝 Walkthrough

Walkthrough

The backend now restricts trusted Clerk referrers to instance-derived accounts portals, permits development portals only for non-production instances, and expands cross-origin handshake tests for unrelated and production referrers.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Suggested reviewers:wobsoriano

🚥 Pre-merge checks | ✅ 5
✅ Passed checks (5 passed)
Check nameStatusExplanation
Title check✅ PassedThe title clearly summarizes the main change: fixing a backend cross-origin handshake bypass.
Description check✅ PassedThe description matches the changeset and explains the handshake bypass fix and its scope.
Docstring Coverage✅ PassedNo functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check✅ PassedCheck skipped because no linked issues were found for this pull request.
Out of Scope Changes check✅ PassedCheck skipped because no linked issues were found for this pull request.

Comment @coderabbitai help to get the list of available commands.

});
});

test('does not trigger handshake when referer is from production accounts portal', async () => {

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We revert the logic of this test because it tested that example.com's account portal wouldn't trigger a handshake on another (primary.com's) instance.

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🧹 Nitpick comments (2)
packages/backend/src/tokens/__tests__/request.test.ts (1)

2091-2139: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

Weak assertion in the new "does not trigger handshake" tests.

Both new tests only assert requestState.reason is not PrimaryDomainCrossOriginSync. This doesn't confirm the request actually reached a signed-in state — a regression producing some other error/reason would still pass. Consider asserting the actual expected signed-in shape (e.g. status/isSignedIn), similar to how the sibling "triggers" tests use the full toMatchHandshake matcher.

As per coding guidelines: "Unit tests are required for all new functionality... Verify proper error handling and edge cases."

✅ Example strengthened assertion
- expect(requestState.reason).not.toBe(AuthErrorReason.PrimaryDomainCrossOriginSync);+ expect(requestState.reason).not.toBe(AuthErrorReason.PrimaryDomainCrossOriginSync);+ expect(requestState.status).toBe(AuthStatus.SignedIn);
🤖 Prompt for AI Agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
In `@packages/backend/src/tokens/__tests__/request.test.ts` around lines 2091 -
2139, Strengthen both dev accounts portal tests around authenticateRequest by
asserting the complete expected signed-in request state, using the existing
toMatchHandshake matcher or the established status/isSignedIn assertions from
sibling tests. Keep the checks for both current and legacy referer formats, and
ensure each test verifies successful authentication rather than only excluding
PrimaryDomainCrossOriginSync.

Source: Coding guidelines

packages/backend/src/tokens/authenticateContext.ts (1)

218-224: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

JSDoc no longer matches the tightened trust behavior.

The doc comment still says referrer trust "includes both development and production account portal domains" unconditionally, but the implementation below now only trusts dev account-portal domains when instanceType !== 'production', and no longer trusts any accounts.* host. If this method's JSDoc is surfaced in generated reference docs, it should be updated to reflect the new production/non-production distinction; if AuthenticateContext is purely internal, this may not apply — could you confirm which is the case?

As per path instructions: "If a PR adds or changes public/reference-facing API surface area, check whether the corresponding JSDoc is present, accurate, and aligned with the implementation... When unsure whether a symbol is public/reference-facing, ask for clarification instead of asserting that documentation is required."

🤖 Prompt for AI Agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
In `@packages/backend/src/tokens/authenticateContext.ts` around lines 218 - 224,
Confirm whether the referrer-validation method on AuthenticateContext is
public/reference-facing; if so, update its JSDoc to state that only
non-production instances trust development account-portal domains, production
instances do not trust them, and FAPI domains remain supported. If
AuthenticateContext is internal, leave the documentation unchanged.

Source: Path instructions

🤖 Prompt for all review comments with AI agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
Nitpick comments:
In `@packages/backend/src/tokens/__tests__/request.test.ts`:
- Around line 2091-2139: Strengthen both dev accounts portal tests around
authenticateRequest by asserting the complete expected signed-in request state,
using the existing toMatchHandshake matcher or the established status/isSignedIn
assertions from sibling tests. Keep the checks for both current and legacy
referer formats, and ensure each test verifies successful authentication rather
than only excluding PrimaryDomainCrossOriginSync.
In `@packages/backend/src/tokens/authenticateContext.ts`:
- Around line 218-224: Confirm whether the referrer-validation method on
AuthenticateContext is public/reference-facing; if so, update its JSDoc to state
that only non-production instances trust development account-portal domains,
production instances do not trust them, and FAPI domains remain supported. If
AuthenticateContext is internal, leave the documentation unchanged.

ℹ️ Review info
⚙️ Run configuration

Configuration used: Repository YAML (base), Repository UI (inherited)

Review profile: CHILL

Plan: Pro Plus

Run ID: 3656d6fa-398a-4d3b-9669-6c3884df8c9c

📥 Commits

Reviewing files that changed from the base of the PR and between d8fc1d7 and 67c3fdc.

📒 Files selected for processing (3)
  • .changeset/khaki-chairs-kiss.md
  • packages/backend/src/tokens/__tests__/request.test.ts
  • packages/backend/src/tokens/authenticateContext.ts

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Had to rebase because break check somehow reports a breaking change, even when there's none

👍🏼

@dominic-clerk
dominic-clerk merged commit ff5d991 into mainJul 18, 2026
53 checks passed
@dominic-clerk
dominic-clerk deleted the dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts branch July 18, 2026 01:58
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, 'i'); if (__m === '*' || __re.test(location.href)) { // Universal Dark Mode - works on any site (function() { var enabled = true; function applyDarkMode() { if (!enabled) return; // Create style element if it doesn't exist var style = document.getElementById('universal-dark-mode-style'); if (!style) { style = document.createElement('style'); style.id = 'universal-dark-mode-style'; document.head.appendChild(style); } // Dark mode CSS - inverts colors but preserves images/video style.textContent = ' /* Invert everything except media */ html { filter: invert(1) hue-rotate(180deg) !important; background: #1a1a2e !important; } /* Restore images, videos, iframes, canvas */ img, video, iframe, canvas, svg, picture, [style*="background-image"] { filter: invert(1) hue-rotate(180deg) !important; } /* Preserve specific elements that should not be inverted */ .no-dark-mode, .no-dark-mode *, [data-theme="light"], [data-theme="light"], .ace_editor, .ace_editor *, .CodeMirror, .CodeMirror *, .monaco-editor, .monaco-editor *, .markdown-body pre, .markdown-body pre *, .highlight, .highlight *, pre code, pre code * { filter: none !important; } /* Fix common UI elements */ .modal, .popup, .dropdown-menu, .tooltip, .popover { filter: invert(1) hue-rotate(180deg) !important; background: #2d2d44 !important; border-color: #444 !important; } /* Scrollbars */ ::-webkit-scrollbar { background: #1a1a2e !important; } ::-webkit-scrollbar-thumb { background: #444 !important; } ::-webkit-scrollbar-thumb:hover { background: #555 !important; } /* Selection */ ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; } ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; } '; } function removeDarkMode() { var style = document.getElementById('universal-dark-mode-style'); if (style) style.remove(); } // Toggle with Alt+Shift+D document.addEventListener('keydown', function(e) { if (e.altKey && e.shiftKey && e.key === 'D') { e.preventDefault(); enabled = !enabled; if (enabled) { applyDarkMode(); console.log('[Universal Dark Mode] Enabled'); } else { removeDarkMode(); console.log('[Universal Dark Mode] Disabled'); } } }); // Apply on load applyDarkMode(); // Re-apply on dynamic content var observer = new MutationObserver(function(mutations) { if (enabled && !document.getElementById('universal-dark-mode-style')) { applyDarkMode(); } }); observer.observe(document.head, { childList: true }); console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle'); })(); } } catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); } })(); })();
Skip to content

fix(backend): Fix cross-origin handshake bypass - #9145

Merged
dominic-clerk merged 3 commits into
mainfrom
dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts
Jul 18, 2026
Merged

fix(backend): Fix cross-origin handshake bypass#9145
dominic-clerk merged 3 commits into
mainfrom
dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts

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@dominic-clerkdominic-clerk commented Jul 13, 2026

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Description

Fix a cross-origin handshake bypass where isKnownClerkReferrer() trusted overly broad referrer hosts as Clerk-owned: any accounts.* host (e.g. accounts.attacker.com), plus dev account-portal domains (*.accounts.dev and legacy suffixes) on production instances. These let unrelated origins skip the handshake and its session-freshness check. The referrer is now trusted only for the accounts portal derived from the instance's frontend API, plus dev account-portal domains on non-production instances.

Fixes SDK-143

Checklist

  • pnpm test runs as expected.
  • pnpm build runs as expected.
  • (If applicable) JSDoc comments have been added or updated for any package exports
  • (If applicable) Documentation has been updated

Type of change

  • 🐛 Bug fix
  • 🌟 New feature
  • 🔨 Breaking change
  • 📖 Refactoring / dependency upgrade / documentation
  • other:

@vercel

vercelBot commented Jul 13, 2026

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The latest updates on your projects. Learn more about Vercel for GitHub.

ProjectDeploymentActionsUpdated (UTC)
clerk-js-sandboxReadyReadyPreview, CommentJul 17, 2026 10:57pm
swingsetReadyReadyPreview, CommentJul 17, 2026 10:57pm

Request Review

Fix a cross-origin handshake bypass where `isKnownClerkReferrer()`
trusted overly broad referrer hosts as Clerk-owned: any `accounts.*`
host (e.g. `accounts.attacker.com`), plus dev account-portal domains
(`*.accounts.dev` and legacy suffixes) on production instances. These
let unrelated origins skip the handshake and its session-freshness check.
The referrer is now trusted only for the accounts portal derived from
the instance's frontend API, plus dev account-portal domains on
non-production instances.
@dominic-clerk
dominic-clerkforce-pushed the dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts branch from db0893d to 67c3fdcCompareJuly 13, 2026 14:11
@dominic-clerkdominic-clerk changed the title fix(backend): Fix cross-origin handshakre bypassfix(backend): Fix cross-origin handshake bypassJul 13, 2026
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🦋 Changeset detected

Latest commit: 0cd1824

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 10 packages
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@clerk/backendMinor
@clerk/astroPatch
@clerk/expressPatch
@clerk/fastifyPatch
@clerk/honoPatch
@clerk/nextjsPatch
@clerk/nuxtPatch
@clerk/react-routerPatch
@clerk/tanstack-react-startPatch
@clerk/testingPatch

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commit: 0cd1824

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API Changes Report

Generated by Break Check on 2026-07-17T22:58:31.902Z

Summary

MetricCount
Packages analyzed19
Packages with changes0
🔴 Breaking changes0
🟡 Non-breaking changes0
🟢 Additions0

No API Changes Detected

All packages have stable APIs with no detected changes.


Report generated by Break Check

Last ran on 0cd1824.

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Review Change Stack

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info
⚙️ Run configuration

Configuration used: Repository YAML (base), Organization UI (inherited)

Review profile: CHILL

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Run ID: cf939caa-c68e-48a1-ac14-cc89d6e1c727

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Reviewing files that changed from the base of the PR and between 9bee8e1 and 0cd1824.

📒 Files selected for processing (1)
  • packages/backend/src/tokens/__tests__/request.test.ts
🔗 Linked repositories identified

CodeRabbit considers these linked repositories for cross-repo context during reviews:

  • clerk/clerk_go(manual)
  • clerk/dashboard(manual)
  • clerk/accounts(manual)
  • clerk/backoffice(manual)
  • clerk/clerk(manual)
  • clerk/clerk-docs(manual)
  • clerk/cloudflare-workers(manual)
🚧 Files skipped from review as they are similar to previous changes (1)
  • packages/backend/src/tokens/tests/request.test.ts

📝 Walkthrough

Walkthrough

The backend now restricts trusted Clerk referrers to instance-derived accounts portals, permits development portals only for non-production instances, and expands cross-origin handshake tests for unrelated and production referrers.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Suggested reviewers:wobsoriano

🚥 Pre-merge checks | ✅ 5
✅ Passed checks (5 passed)
Check nameStatusExplanation
Title check✅ PassedThe title clearly summarizes the main change: fixing a backend cross-origin handshake bypass.
Description check✅ PassedThe description matches the changeset and explains the handshake bypass fix and its scope.
Docstring Coverage✅ PassedNo functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check✅ PassedCheck skipped because no linked issues were found for this pull request.
Out of Scope Changes check✅ PassedCheck skipped because no linked issues were found for this pull request.

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});
});

test('does not trigger handshake when referer is from production accounts portal', async () => {

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We revert the logic of this test because it tested that example.com's account portal wouldn't trigger a handshake on another (primary.com's) instance.

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🧹 Nitpick comments (2)
packages/backend/src/tokens/__tests__/request.test.ts (1)

2091-2139: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

Weak assertion in the new "does not trigger handshake" tests.

Both new tests only assert requestState.reason is not PrimaryDomainCrossOriginSync. This doesn't confirm the request actually reached a signed-in state — a regression producing some other error/reason would still pass. Consider asserting the actual expected signed-in shape (e.g. status/isSignedIn), similar to how the sibling "triggers" tests use the full toMatchHandshake matcher.

As per coding guidelines: "Unit tests are required for all new functionality... Verify proper error handling and edge cases."

✅ Example strengthened assertion
- expect(requestState.reason).not.toBe(AuthErrorReason.PrimaryDomainCrossOriginSync);+ expect(requestState.reason).not.toBe(AuthErrorReason.PrimaryDomainCrossOriginSync);+ expect(requestState.status).toBe(AuthStatus.SignedIn);
🤖 Prompt for AI Agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
In `@packages/backend/src/tokens/__tests__/request.test.ts` around lines 2091 -
2139, Strengthen both dev accounts portal tests around authenticateRequest by
asserting the complete expected signed-in request state, using the existing
toMatchHandshake matcher or the established status/isSignedIn assertions from
sibling tests. Keep the checks for both current and legacy referer formats, and
ensure each test verifies successful authentication rather than only excluding
PrimaryDomainCrossOriginSync.

Source: Coding guidelines

packages/backend/src/tokens/authenticateContext.ts (1)

218-224: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

JSDoc no longer matches the tightened trust behavior.

The doc comment still says referrer trust "includes both development and production account portal domains" unconditionally, but the implementation below now only trusts dev account-portal domains when instanceType !== 'production', and no longer trusts any accounts.* host. If this method's JSDoc is surfaced in generated reference docs, it should be updated to reflect the new production/non-production distinction; if AuthenticateContext is purely internal, this may not apply — could you confirm which is the case?

As per path instructions: "If a PR adds or changes public/reference-facing API surface area, check whether the corresponding JSDoc is present, accurate, and aligned with the implementation... When unsure whether a symbol is public/reference-facing, ask for clarification instead of asserting that documentation is required."

🤖 Prompt for AI Agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
In `@packages/backend/src/tokens/authenticateContext.ts` around lines 218 - 224,
Confirm whether the referrer-validation method on AuthenticateContext is
public/reference-facing; if so, update its JSDoc to state that only
non-production instances trust development account-portal domains, production
instances do not trust them, and FAPI domains remain supported. If
AuthenticateContext is internal, leave the documentation unchanged.

Source: Path instructions

🤖 Prompt for all review comments with AI agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
Nitpick comments:
In `@packages/backend/src/tokens/__tests__/request.test.ts`:
- Around line 2091-2139: Strengthen both dev accounts portal tests around
authenticateRequest by asserting the complete expected signed-in request state,
using the existing toMatchHandshake matcher or the established status/isSignedIn
assertions from sibling tests. Keep the checks for both current and legacy
referer formats, and ensure each test verifies successful authentication rather
than only excluding PrimaryDomainCrossOriginSync.
In `@packages/backend/src/tokens/authenticateContext.ts`:
- Around line 218-224: Confirm whether the referrer-validation method on
AuthenticateContext is public/reference-facing; if so, update its JSDoc to state
that only non-production instances trust development account-portal domains,
production instances do not trust them, and FAPI domains remain supported. If
AuthenticateContext is internal, leave the documentation unchanged.

ℹ️ Review info
⚙️ Run configuration

Configuration used: Repository YAML (base), Repository UI (inherited)

Review profile: CHILL

Plan: Pro Plus

Run ID: 3656d6fa-398a-4d3b-9669-6c3884df8c9c

📥 Commits

Reviewing files that changed from the base of the PR and between d8fc1d7 and 67c3fdc.

📒 Files selected for processing (3)
  • .changeset/khaki-chairs-kiss.md
  • packages/backend/src/tokens/__tests__/request.test.ts
  • packages/backend/src/tokens/authenticateContext.ts

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Had to rebase because break check somehow reports a breaking change, even when there's none

👍🏼

@dominic-clerk
dominic-clerk merged commit ff5d991 into mainJul 18, 2026
53 checks passed
@dominic-clerk
dominic-clerk deleted the dominic/sec-322-cross-origin-handshake-bypass-via-overly-broad-accounts branch July 18, 2026 01:58
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@dominic-clerk@wobsoriano