Official Clerk JavaScript SDKs: Middleware-based route protection bypass - @clerk/astro

Description

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.

Sessions are not compromised and no existing user can be impersonated - the bypass only affects the middleware-level gating decision.

Recommendation

Update the @clerk/astro package to the latest compatible version. Followings are version details:

• Affected version(s): **>= 3.0.0, < 3.0.15

  >= 2.0.0-snapshot.v20241206174604, <= 2.17.9

  >= 0.0.1, < 1.5.7**

• Patched version(s): **3.0.15

  2.17.10

  1.5.7**

References

• GHSA-vqx2-fgx2-5wq9
• CVE-2026-41248
• CWE-436
• CWE-863
• CAPEC-310
• OWASP 2021-A1
• OWASP 2021-A6

Related Issues

• Official Clerk JavaScript SDKs: Middleware-based route protection bypass - CVE-2026-41248
• Official Clerk JavaScript SDKs: Middleware-based route protection bypass - @clerk/shared - CVE-2026-41248
• Official Clerk JavaScript SDKs: Middleware-based route protection bypass - @clerk/nextjs - CVE-2026-41248
• Clerk has an authorization bypass when combining organization, billing, or reverification checks - @clerk/astro - CVE-2026-42349

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Tags:

npm

@clerk/astro