CVE-2026-44572
Next.js: Middleware / Proxy redirects can be cache-poisoned
- Published
- May 13, 2026
- Updated
- May 14, 2026
- Assigning CNA
- GitHub_M
- Evidence observed
- Aug 25, 2026
Primary CVSS
nvd · CVSS 3.1
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:HLow · next 30 days
- Percentile
- 21.1%
- Model date
- Sep 21, 2026
EPSS is a statistical estimate, not a certainty or a measure of impact. Combine it with CVSS, KEV status, exposure and your environment.
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.
Sources
1Next.js v16.2.4 Security PoC Collection (CVE-2026-23870, CVE-2026-44575, CVE-2026-44579, CVE-2026-44574, CVE-2026-44578, CVE-2026-44573, CVE-2026-44581, CVE-2026-44580, CVE-2026-44577, CVE-2026-44576, CVE-2026-44582, CVE-2026-44572)
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