CVE-2026-41248

Official Clerk JavaScript SDKs: Middleware-based route protection bypass

State: Published
Severity: 9.1 Critical
Published: Apr 24, 2026
Updated: Apr 27, 2026
Reserved: Apr 18, 2026

Description

Clerk JavaScript is the official JavaScript repository for Clerk authentication. createRouteMatcher in @clerk/nextjs, @clerk/nuxt, and @clerk/astro can be bypassed by certain crafted requests, allowing them to skip middleware gating and reach downstream handlers. This vulnerability is fixed in @clerk/astro 1.5.7, 2.17.10, and 3.0.15; @clerk/nextjs 5.7.6, 6.39.2, and 7.2.1; @clerk/nuxt 1.13.28 and 2.2.2; and @clerk/shared 2.22.1, 3.47.4, anc 4.8.1

Scores

CVSS	Score	Vector	Source
3.1	9.1 Critical	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N	GitHub_M

Weaknesses

CWE-436 Interpretation Conflict
CWE-863 Incorrect Authorization

Affected Products

Product	Versions
astroclerk	>= 0.0.1, < 1.5.7Affected >= 2.0.0-snapshot.v20241206174604, <= 2.17.9Affected >= 3.0.0, < 3.0.15Affected
nextjsclerk	>= 5.0.0, < 5.7.6Affected >= 6.0.0-snapshot.vb87a27f, < 6.39.2Affected >= 7.0.0, < 7.2.1Affected
nuxtclerk	>= 1.1.0, < 1.13.28Affected >= 2.0.0, < 2.2.2Affected
sharedclerk	>= 2.20.17, < 2.22.1Affected >= 3.0.0-canary.v20250225091530, < 3.47.4Affected >= 4.0.0, < 4.8.1Affected

References

https://github.com/clerk/javascript/security/advisories/GHSA-vqx2-fgx2-5wq9

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