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

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.

Next.js contains a critical middleware bypass vulnerability affecting versions 11.1.4 through 15.2.2.
The vulnerability allows attackers to bypass middleware security controls by sending a specially crafted
'x-middleware-subrequest' header, which can lead to authorization bypass and other security control circumvention.

 id: CVE-2025-29927

info:
  name: Next.js Middleware Bypass
  author: pdresearch,pdteam,hazedic
  se

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