CVE-2025-29927 PoC — Authorization Bypass in Next.js Middleware

Source

https://github.com/Balajih4kr/cve-2025-29927

Associated Vulnerability

Title:Authorization Bypass in Next.js Middleware (CVE-2025-29927)
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.

Description

CVE-2025-29927 is a critical vulnerability in Next.js, a popular React-based web framework. The flaw exists in how the middleware feature handles certain internal headers — specifically, the x-middleware-subrequest header

Readme

# cve-2025-29927
CVE-2025-29927 is a critical vulnerability in Next.js, a popular React-based web framework. The flaw exists in how the middleware feature handles certain internal headers — specifically, the x-middleware-subrequest header

File Snapshot

Remarks

1. It is advised to access via the original source first.

2. Local POC snapshots are reserved for subscribers — if the original source is unavailable, the local mirror is part of the paid plan.

View subscription plans →

Goal Reached Thanks to every supporter — we hit 100%!