CVE-2025-29927
CRITICALAuthorization Bypass in Next.js Middleware
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
next📦next📦next📦nextReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.
Description
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 bypass authorization checks within a Next.js application, if the authorization check occurs in middleware. If patching to a safe version is infeasible, it is recommend that you prevent external user requests which contain the x-middleware-subrequest header from reaching your Next.js application. This vulnerability is fixed in 12.3.5, 13.5.9, 14.2.25, and 15.2.3.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | next | ≥ 13.0.0&&< 13.5.9 | 13.5.9 |
| 📦npm | next | ≥ 14.0.0&&< 14.2.25 | 14.2.25 |
| 📦npm | next | ≥ 15.0.0&&< 15.2.3 | 15.2.3 |
| 📦npm | next | ≥ 12.0.0&&< 12.3.5 | 12.3.5 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Next.js Middleware 15.2.2 - Authorization Bypass
by kOaDT · Apr 5, 2025
Frequently Asked Questions
Is CVE-2025-29927 in your stack?
O3 detects CVE-2025-29927 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.