CVE-2026-42349

8.1 · HIGH

Clerk JavaScript is the official JavaScript repository for Clerk authentication.

Published May 11, 2026clerkCWE-754EPSS 0.25%CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Overview

CVE-2026-42349 is a high-severity vulnerability affecting clerk clerk\/astro. It was published on May 11, 2026 and has a CVSS 3.1 base score of 8.1 (HIGH).

This vulnerability has a CVSS 3.1 base score of 8.1, rated HIGH. It can be exploited remotely over the network. Some level of privileges is required for exploitation.

Technical description

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.

Remediation

Check the references section for vendor advisories and patches from clerk. Update clerk\/astro to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Affected products

Vendor	Product	Versions	Status
clerk	clerk\/astro	>= 2.0.0, < 2.17.11	Affected
clerk	clerk\/backend	>= 2.0.0, < 2.33.3	Affected
clerk	clerk\/chrome-extension	>= 1.3.5, < 2.9.15	Affected
clerk	clerk\/clerk-expo	>= 2.2.11, < 2.19.36	Affected
clerk	clerk\/clerk-js	>= 5.22.0, < 5.125.10	Affected
clerk	clerk\/clerk-react	>= 5.9.0, < 5.61.6	Affected
clerk	clerk\/expo	>= 3.0.0, < 3.2.2	Affected
clerk	clerk\/express	>= 0.1.0, < 1.7.79	Affected
clerk	clerk\/fastify	>= 1.0.42, < 2.6.31	Affected
clerk	clerk\/hono	>= 0.0.2, < 0.1.16	Affected
clerk	clerk\/nextjs	6.0.0	Affected
clerk	clerk\/nuxt	>= 1.0.0, < 1.13.29	Affected
clerk	clerk\/react	>= 6.0.0, < 6.4.3	Affected
clerk	clerk\/react-router	>= 0.0.1, < 2.4.13	Affected
clerk	clerk\/shared	>= 3.0.0, < 3.47.5	Affected
clerk	clerk\/tanstack-react-start	>= 0.0.1, < 0.29.11	Affected
clerk	clerk\/vue	>= 1.0.0, < 1.17.21	Affected

References

GitHubgithub.com/clerk/javascript/security/advisories/GHSA-w24r-5266-9c3c GitHubgithub.com/clerk/javascript/security/advisories/GHSA-w24r-5266-9c3c

How CyberStrike helps

Frequently asked questions

What is CVE-2026-42349?

CVE-2026-42349 is a high-severity vulnerability affecting clerk clerk\/astro. It was published on May 11, 2026 and has a CVSS 3.1 base score of 8.1 (HIGH).

How severe is CVE-2026-42349?

This vulnerability has a CVSS 3.1 base score of 8.1, rated HIGH. It can be exploited remotely over the network. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2026-42349?

How can CyberStrike help with CVE-2026-42349?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-42349 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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