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CVE-2026-44572GHSA-3G8H-86W9-WVMQ

Next.js: Middleware / Proxy redirects can be cache-poisoned

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 15.5.16, 16.2.5
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: partial

Summary

Next.js is a React framework for building full-stack web applications. From 12.2.0 to before 15.5.16 and 16.2.5, an external client could send a x-nextjs-data header on a normal request to a path handled by middleware that returns a redirect. When that happened, the middleware/proxy could treat the request as a data request and replace the standard Location redirect header with the internal x-nextjs-redirect header. Browsers do not follow x-nextjs-redirect, so the response became an unusable redirect for normal clients. If the application was deployed behind a CDN or reverse proxy that caches 3xx responses without varying on this header, a single attacker request could poison the cached redirect response for the affected path. Subsequent visitors could then receive a cached redirect response without a Location header, causing a denial of service for that redirect path until the cache entry expired or was purged. This vulnerability is fixed in 15.5.16 and 16.2.5.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: partial

  3. Record last updated

Affected versions

  • vercel next.js

    From 12.2.0 · fixed in 15.5.16; From 16.0.0 · fixed in 16.2.5

  • nextnpm

    From 12.2.0 · fixed in 15.5.16

  • nextnpm

    From 16.0.0 · fixed in 16.2.5

References 1

GitHub · vercel/next.js