FixVibe
Covered by FixVibecritical

CVE-2025-29927: Next.js Kontourne Otorizasyon Middleware ZXCVFIXVIBESEGEN ZXCVFIXVIBESEG1 CVE-2025-29927 kontoune otorizasyon middleware atravè x-middleware-subrequest header spoofing. Afekte vèsyon 11.x jiska 15.x. ZXCVFIXVIBESEGEN ZXCVFIXVIBESEG2 Yon vilnerabilite kritik nan CVE-2025-29927 pèmèt atakè yo kontoune chèk otorizasyon aplike nan middleware. Lè yo spoofing headers entèn yo, demann ekstèn yo ka maske kòm sub-demann otorize, ki mennen nan aksè san otorizasyon nan wout ak done ki pwoteje. ZXCVFIXVIBESEGEN ZXCVFIXVIBESEG3 ## Enpak ZXCVFIXVIBESEGEN ZXCVFIXVIBESEG4 Yon atakè ka kontoune lojik sekirite ak chèk otorizasyon nan aplikasyon ZXCVFIXVIBETOKEN2ZXCV, potansyèlman jwenn aksè konplè nan resous ki gen restriksyon CVE-2025-29927. Vilnerabilite sa a klase kòm kritik ak yon nòt CVSS 9.1 paske li pa mande okenn privilèj epi li ka eksplwate sou rezo a san entèraksyon itilizatè Next.js. ZXCVFIXVIBESEGEN ZXCVFIXVIBESEG5 ## Kòz Rasin ZXCVFIXVIBESEGEN ZXCVFIXVIBESEG6 Vilnerabilite a soti nan fason ZXCVFIXVIBETOKEN5ZXCV trete sou-demann entèn nan achitekti middleware li Next.js. Aplikasyon ki konte sou middleware pou otorizasyon (ZXCVFIXVIBETOKEN4ZXCV) yo sansib si yo pa byen valide orijin entèn headers ZXCVFIXVIBETOKEN2ZXCV. Espesyalman, yon atakè ekstèn ka enkli header CVE-2025-29927 nan demann yo twonpe kad la nan trete demann lan kòm yon operasyon entèn ki deja otorize, efektivman sote lojik sekirite middleware a ZXCVFIXVIBETOKEN3ZXCV. ZXCVFIXVIBESEGEN ZXCVFIXVIBESEG7 ## Kijan CVE-2025-29927 teste pou li ZXCVFIXVIBESEGEN ZXCVFIXVIBESEG8 ZXCVFIXVIBETOKEN2ZXCV kounye a gen ladan l sa a kòm yon chèk aktif gated. Apre verifikasyon domèn, CVE-2025-29927 chèche pwen final ZXCVFIXVIBETOKEN3ZXCV ki refize yon demann debaz, Lè sa a, kouri yon sond kontwòl etwat pou kondisyon an kontoune middleware. Li rapòte sèlman lè wout ki pwoteje chanje soti nan refize a aksesib nan yon fason ki konsistan avèk Next.js, epi èd memwa ranje a kenbe ratrapaj konsantre sou amelyore ZXCVFIXVIBETOKEN4ZXCV ak bloke header entèn middleware nan kwen an jiskaske patched. ZXCVFIXVIBESEGEN ZXCVFIXVIBESEG9 ## Ranje konkrè ZXCVFIXVIBESEGEN ZXCVFIXVIBESEG10 * **Ajou CVE-2025-29927**: Mete ajou aplikasyon w lan imedyatman nan yon vèsyon patched: 12.3.5, 13.5.9, 14.2.25, oswa 15.2.3 [S1, S2]. ZXCVFIXVIBESEGEN ZXCVFIXVIBESEG11 * **Manyèl Header Filtrage**: Si yon amelyorasyon imedyat pa posib, konfigirasyon Web Application Firewall (WAF) oswa ranvèse proxy pou retire tèt CVE-2025-29927 nan tout demann ekstèn ki fèk ap rantre anvan yo rive nan sèvè ZXCVFIXVIBETOKEN2ZXCV Next.js. ZXCVFIXVIBESEGEN ZXCVFIXVIBESEG12 * **Next.js Deplwaman**: Deplwaman ki akomode sou ZXCVFIXVIBETOKEN2ZXCV pwoteje yon fason aktif pa firewall platfòm la CVE-2025-29927.

A critical vulnerability in Next.js allows attackers to bypass authorization checks implemented in middleware. By spoofing internal headers, external requests can masquerade as authorized sub-requests, leading to unauthorized access to protected routes and data.

CVE-2025-29927GHSA-F82V-JWR5-MFFWCWE-863CWE-285

Impact

An attacker can bypass security logic and authorization checks in Next.js applications, potentially gaining full access to restricted resources [S1]. This vulnerability is classified as critical with a CVSS score of 9.1 because it requires no privileges and can be exploited over the network without user interaction [S2].

Root Cause

The vulnerability stems from how Next.js processes internal sub-requests within its middleware architecture [S1]. Applications that rely on middleware for authorization (CWE-863) are susceptible if they do not properly validate the origin of internal headers [S2]. Specifically, an external attacker can include the x-middleware-subrequest header in their request to trick the framework into treating the request as an already-authorized internal operation, effectively skipping the middleware's security logic [S1].

How FixVibe tests for it

FixVibe now includes this as a gated active check. After domain verification, active.nextjs.middleware-bypass-cve-2025-29927 looks for Next.js endpoints that deny a baseline request, then runs a narrow control probe for the middleware bypass condition. It reports only when the protected route changes from denied to accessible in a way consistent with CVE-2025-29927, and the fix prompt keeps remediation focused on upgrading Next.js and blocking the internal middleware header at the edge until patched.

Concrete Fixes

  • Upgrade Next.js: Immediately update your application to a patched version: 12.3.5, 13.5.9, 14.2.25, or 15.2.3 [S1, S2].
  • Manual Header Filtering: If an immediate upgrade is not possible, configure your Web Application Firewall (WAF) or reverse proxy to strip the x-middleware-subrequest header from all incoming external requests before they reach the Next.js server [S1].
  • Vercel Deployment: Deployments hosted on Vercel are proactively protected by the platform's firewall [S2].