clerk javascript unusual condition

Summaryinfo

A vulnerability was found in clerk javascript, shared, backend, nextjs, -react, react, vue, astro, nuxt, -expo, expo, react-router, tanstack-react-start, chrome-extension, fastify, express and hono and classified as critical. Affected is an unknown function. Such manipulation leads to unusual condition. This vulnerability is uniquely identified as CVE-2026-42349. The attack can be launched remotely. No exploit exists. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, has been found in clerk javascript, shared, backend, nextjs, -react, react, vue, astro, nuxt, -expo, expo, react-router, tanstack-react-start, chrome-extension, fastify, express and hono. Affected by this issue is an unknown code. The manipulation with an unknown input leads to a unusual condition vulnerability. Using CWE to declare the problem leads to CWE-754. The product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product. Impacted is confidentiality, integrity, and availability. CVE summarizes:

Clerk JavaScript is the official JavaScript repository for Clerk authentication. 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. 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. This vulnerability is fixed in @clerk/clerk-js 5.125.10 and 6.7.5.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-42349 since 04/26/2026. The exploitation is known to be easy. The attack may be launched remotely. The technical details are unknown and an exploit is not available.

Upgrading eliminates this vulnerability.

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Productinfo

Type

• Router Operating System

Vendor

• clerk

Name

• -expo
• -react
• astro
• backend
• chrome-extension
• expo
• express
• fastify
• hono
• javascript
• nextjs
• nuxt
• react
• react-router
• shared
• tanstack-react-start
• vue

Website

• Product: https://github.com/clerk/javascript/

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