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.
History

Wed, 13 May 2026 19:00:00 +0000

Type Values Removed Values Added
First Time appeared Vercel
Vercel next.js
Vendors & Products Vercel
Vercel next.js

Wed, 13 May 2026 16:15:00 +0000

Type Values Removed Values Added
Description 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.
Title Next.js: Middleware / Proxy redirects can be cache-poisoned
Weaknesses CWE-349
References
Metrics cvssV3_1

{'score': 3.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-05-13T15:57:15.750Z

Updated: 2026-05-13T15:57:15.750Z

Reserved: 2026-05-06T21:49:12.424Z

Link: CVE-2026-44572

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-05-13T16:16:58.800

Modified: 2026-05-13T16:58:40.557

Link: CVE-2026-44572

cve-icon Redhat

No data.