# CVE-2026-42349: @clerk/shared — Fixed in 3.47.5 📦 npm Not in CISA KEV # CVE-2026-42349 — @clerk/shared CVE-2026-42349 is a CWE-754 vulnerability in @clerk/shared. A fix is available for @clerk/shared — see the affected versions and patch details below. Clerk: Authorization bypass when combining organization, billing, or reverification checks Also known as[GHSA-w24r-5266-9c3c](/vulnerability/GHSA-w24r-5266-9c3c) Published May 11, 2026 Updated Oct 28, 2026 Affected 29 pkgs Patched 29 / 29 Exploits None indexed Exploitation data as of Nov 9, 2026 · OSV.dev, NVD, FIRST.org (EPSS) ## Exploitation Status ### Proof-of-concept exploit code exists - CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation. Exploitation and automatability from CISA’s SSVC triage for CVE-2026-42349. ## EPSS Exploitation Probability [via FIRST.org ↗](https://www.first.org/epss/) 0.2%probability of exploitation in next 30 days Lower Risk0.00% Lower risk than most CVEs16th percentile — riskier than 16% of all scored CVEsHighest risk 0.00%0.31%0.62%0.93%0.1%0.2%Jun 26Sep 26Nov 26 Probability of exploitation in the next 30 days, from [FIRST.org EPSS](https://www.first.org/epss/). ## Real-World Exposure 29 pkgs affected How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched. 75other npm packages depend on this — each one inherits the vulnerability until it's patched upstream `@clerk/shared`npm 10.2Mdownloads / week `@clerk/backend`npm 7.5Mdownloads / week ## Description #### Summary `has()`, `auth.protect()`, and related authorization predicates in `@clerk/shared`, `@clerk/nextjs`, `@clerk/backend`, and other framework SDKs can return true for certain combined authorization checks when the result should be false, allowing a gated action to proceed for a user who does not satisfy the full set of requested conditions. Sessions are not compromised and no existing user can be impersonated. The bypass is limited to the authorization decision returned by the predicate. `clerkMiddleware` continues to authenticate requests correctly, `auth()` reflects the real authentication state, and token verification is unaffected. #### Who is affected All apps that combine more than one authorization dimension in a single `has()` or `auth.protect()` call should upgrade to the patched versions. Patches are drop-in with no API changes. The information below describes the scope of the bypass and helps developers understand whether their apps are potentially affected, but is not a reason to delay the upgrade. This call shape can be bypassed if certain conditions are met: a `has()` or `auth.protect()` call that combines a `reverification` check with any of `role`, `permission`, `feature`, or `plan`, or that combines a billing check (`feature` or `plan`) with a role or permission check. ``` // Reverification combined with role / permission / feature / plan await auth.protect({ permission: 'org:settings:delete', reverification: 'strict' }); const canAct = has({ role: 'org:admin', reverification: 'strict' }); // Billing (feature / plan) combined with role / permission const canAct = has({ permission: 'org:admin', feature: 'premium' }); ``` Single-condition checks are not affected and continue to fail closed as expected: ``` await auth.protect({ permission: 'org:settings:delete' }); has({ reverification: 'strict' }); ``` The callback form of `auth.protect` is not affected unless the callback itself invokes one of the affected shapes: ``` await auth.protect(has => has({ permission: 'org:X' }) && has({ reverification: 'strict' })); ``` App patterns that rely only on single-condition checks, or that combine them via the callback form, are unaffected. Authentication, session state, and token verification continue to work correctly regardless of this bypass. `@clerk/shared` is usually not imported directly in application code, but the fix lives there and reaches an app through its framework package. If developers import `createCheckAuthorization` from `@clerk/shared` directly, their apps are also affected. Run `npm why @clerk/shared` (or the app's package manager's equivalent) to check the installed version. #### Additional `auth.protect()` bypass A second, related bypass lives in `@clerk/nextjs`: `auth.protect()` silently discarded authorization params (`role`, `permission`, `feature`, `plan`, `reverification`) whenever the same argument object also contained `unauthenticatedUrl`, `unauthorizedUrl`, or `token`. #### Recommended actions Upgrade to the latest patch release of the consuming app's framework package on its current major. Both Core 2 and Core 3 release lines have patches. See the "Affected packages" section above for the exact vulnerable ranges and patched versions per package. If a consuming app pins `@clerk/clerk-js` directly, upgrade it to the patched version. Most apps load `@clerk/clerk-js` from Clerk's CDN through their framework package and will receive the fix automatically, with no upgrade step required. #### Workaround If developers cannot upgrade immediately, split combined `has()` or `auth.protect()` calls into sequential single-condition checks: ``` // Replace await auth.protect({ permission: 'org:X', reverification: 'strict' }); // With await auth.protect({ reverification: 'strict' }); await auth.protect({ permission: 'org:X' }); ``` Each single-condition check fails closed as expected, so evaluating them independently and denying if either fails produces the correct result. #### Timeline This issue was reported on 18 APR 2026, patched on 22 APR 2026, and publicly disclosed on 22 APR 2026. Thanks to AISafe for the responsible disclosure of this vulnerability. ## Affected Packages 29 total 29 fixed Ecosystem Package Vulnerable range Fix 📦npm `@clerk/shared` ≥ 3.0.0&&< 3.47.5 3.47.5`npm install @clerk/shared@3.47.5` 📦npm `@clerk/shared` ≥ 4.0.0&&< 4.8.3 4.8.3`npm install @clerk/shared@4.8.3` 📦npm `@clerk/backend` ≥ 2.0.0&&< 2.33.3 2.33.3`npm install @clerk/backend@2.33.3` 📦npm `@clerk/backend` ≥ 3.0.0&&< 3.2.14 3.2.14`npm install @clerk/backend@3.2.14` 📦npm `@clerk/nextjs` ≥ 6.0.0&&< 6.39.3 6.39.3`npm install @clerk/nextjs@6.39.3` 📦npm `@clerk/nextjs` ≥ 7.0.0&&< 7.2.4 7.2.4`npm install @clerk/nextjs@7.2.4` ## Affected Products 17 products · 29 configurations Application `clerk\/astro`clerk ≥ 3.0.0 && < 3.0.18 range Application `clerk\/backend`clerk ≥ 3.0.0 && < 3.2.14 range Application `clerk\/chrome-extension`clerk ≥ 3.0.0 && < 3.1.15 range Application `clerk\/clerk-expo`clerk ≥ 2.2.11 && < 2.19.36 range Application `clerk\/clerk-js`clerk ≥ 6.0.0 && < 6.7.5 range Application `clerk\/clerk-react`clerk ≥ 5.9.0 && < 5.61.6 range ## Detection & mitigation playbook Open-source dependency 1. ### Detect Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @clerk/shared, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version. 2. ### Fix Update @clerk/shared to 3.47.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-42349 is resolved across your whole dependency graph. 3. ### Workarounds Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used. ## Frequently Asked Questions \### Summary \`has()\`, \`auth.protect()\`, and related authorization predicates in \`@clerk/shared\`, \`@clerk/nextjs\`, \`@clerk/backend\`, and other framework SDKs can return true for certain combined authorization checks when the result should be false, allowing a gated action to proceed for a user who does not satisfy the full set of requested conditions. Sessions are not compromised and no existing user can be impersonated. The bypass is limited to the authorization decision returned by the predicate. \`clerkMiddleware\` continues to authenticate requests correctly, \`auth()\` reflects the real authe O3 Security · Impact-Aware SCA ### Is CVE-2026-42349 in your dependencies? Find it across npm, including transitive dependencies. [Scan my dependencies](/book-demo) [How O3 SCA works](/impact-aware-sca)