Authorization Bypass in Next.js Middleware
# Impact It is possible to bypass authorization checks within a Next.js application, if the authorization check occurs in middleware. # Patches * For Next.js 15.x, this issue is fixed in `15.2.3` * For Next.js 14.x, this issue is fixed in `14.2.25` * For Next.js 13.x, this issue is fixed in 13.5.9 * For Next.js 12.x, this issue is fixed in 12.3.5 * For Next.js 11.x, consult the below workaround. _Note: Next.js deployments hosted on Vercel are automatically protected against this vulnerability._ # Workaround If patching to a safe version is infeasible, we recommend that you prevent external user requests which contain the `x-middleware-subrequest` header from reaching your Next.js application. ## Credits - Allam Rachid (zhero;) - Allam Yasser (inzo_)
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2025-29927US | —OT high | Exploit | ||
Next.js is a React framework for building full-stack web applications. Starting in version 1.11.4 and prior to versions 12.3.5, 13.5.9, 14.2.25, and 15.2.3, it is possible to bypas… | ||||
references
External citations — patches, advisories, analysis.
- http://www.openwall.com/lists/oss-security/2025/03/23/3WEB
- http://www.openwall.com/lists/oss-security/2025/03/23/4WEB
- https://github.com/vercel/next.jsPACKAGE
- https://github.com/vercel/next.js/commit/52a078da3884efe6501613c7834a3d02a91676d2WEB
- https://github.com/vercel/next.js/commit/5fd3ae8f8542677c6294f32d18022731eab6fe48WEB
- https://github.com/vercel/next.js/releases/tag/v12.3.5WEB
- https://github.com/vercel/next.js/releases/tag/v13.5.9WEB
- https://github.com/vercel/next.js/security/advisories/GHSA-f82v-jwr5-mffwWEB
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