Next.js is a React framework for building full-stack web applications. In versions 12.0.0 through 15.5.20 and 16.0.0 through 16.2.10, a server-side fetch with a request body may return a cached response body from a different request to the same URL but different body. Confidential data in the POST's response body would then leak to unauthorized requests. Though the request itself will not be deduped. This is only an issue when receiving request bodies with a content type charset other than UTF-8. For example, the UTF-16 byte sequences for 삃삃 and 섄섄 in the request body would share the same cache. This issue has been fixed in versions 15.5.21 and 16.2.11.
Fix
Patch, vendor advisory and mitigation references on NVD 3
- https://github.com/vercel/next.js/commit/025bf4a5f7b47fb7758c4ebf1c931a61c451c082 Patch
- https://github.com/vercel/next.js/pull/96008 Issue Tracking, Patch
- https://github.com/vercel/next.js/security/advisories/GHSA-4633-3j49-mh5q Vendor Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 6.3 · vercelNVD modified 2026-10-24 13:10
Affected (CPE criteria) 1
cpe:2.3:a:vercel:next.js:*:*:*:*:*:node.js:*:*
References 5
- https://github.com/vercel/next.js/commit/025bf4a5f7b47fb7758c4ebf1c931a61c451c082 Patch
- https://github.com/vercel/next.js/pull/96008 Issue Tracking, Patch
- https://github.com/vercel/next.js/releases/tag/v15.5.21 Product, Release Notes
- https://github.com/vercel/next.js/releases/tag/v16.2.11 Product, Release Notes
- https://github.com/vercel/next.js/security/advisories/GHSA-4633-3j49-mh5q Vendor Advisory