CVE-2025-29927
Authorization Bypass in Next.js Middleware
Description
# 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_)
How to fix CVE-2025-29927
To remediate CVE-2025-29927, upgrade the affected package to a fixed version below.
- —upgrade to 13.5.9 or later
Is CVE-2025-29927 being exploited?
Likely — EPSS is 92.1%, placing CVE-2025-29927 in the top tier of vulnerabilities by exploitation probability. Prioritise patching.
Affected packages (1)
- >= 13.0.0, < 13.5.9
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | CRITICAL9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |