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Vulnerability · Published Apr 24, 2026 · Assigned by GitHub_M

CVE-2026-41248Official Clerk JavaScript SDKs: Middleware-based route protection bypass

Critical 9.1

In plain English

A critical-severity incorrect authorization in astro from clerk. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 25% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)9.1Critical
Exploit odds (30 days)0.3%top 74.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
npm@clerk/astro2.17.10GHSA-vqx2-fgx2-5wq9
npm@clerk/astro3.0.15GHSA-vqx2-fgx2-5wq9
npm@clerk/astro1.5.7GHSA-vqx2-fgx2-5wq9
npm@clerk/nextjs5.7.6GHSA-vqx2-fgx2-5wq9
npm@clerk/nextjs6.39.2GHSA-vqx2-fgx2-5wq9
npm@clerk/nextjs7.2.1GHSA-vqx2-fgx2-5wq9
npm@clerk/nuxt2.2.2GHSA-vqx2-fgx2-5wq9
npm@clerk/nuxt1.13.28GHSA-vqx2-fgx2-5wq9
npm@clerk/shared2.22.1GHSA-vqx2-fgx2-5wq9
npm@clerk/shared3.47.4GHSA-vqx2-fgx2-5wq9
npm@clerk/shared4.8.1GHSA-vqx2-fgx2-5wq9

Affected products (as reported)

VendorProductVersions
clerk astro >= 0.0.1, < 1.5.7>= 2.0.0-snapshot.v20241206174604, <= 2.17.9>= 3.0.0, < 3.0.15
clerk nextjs >= 5.0.0, < 5.7.6>= 6.0.0-snapshot.vb87a27f, < 6.39.2>= 7.0.0, < 7.2.1
clerk nuxt >= 1.1.0, < 1.13.28>= 2.0.0, < 2.2.2
clerk shared >= 2.20.17, < 2.22.1>= 3.0.0-canary.v20250225091530, < 3.47.4>= 4.0.0, < 4.8.1

Weakness: CWE-436, CWE-863 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

References