CVE-2026-64647
Next.js: Response Body Cache Confusion with Invalid UTF-8 Request Bodies
MEDIUM 6.3
At a glance
- Source
- NVD
- EPSS
- EPSS 0.32 % · percentile 25 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- GitHub_M
- NVD status
- Analyzed
Description
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.
Weaknesses (CWE)
- CWE-116 — Improper Encoding or Escaping of Output
References
- https://github.com/vercel/next.js/security/advisories/GHSA-4633-3j49-mh5q
- https://github.com/vercel/next.js/pull/96008
- https://github.com/vercel/next.js/commit/025bf4a5f7b47fb7758c4ebf1c931a61c451c082
- https://github.com/vercel/next.js/releases/tag/v15.5.21
- https://github.com/vercel/next.js/releases/tag/v16.2.11
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 4.0 | MEDIUM 6.3 | CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N | GitHub_M |
| CVSS 4.0 | MEDIUM 6.3 | CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X | NVD · security-advisories@github.com (Secondary) |
| CVSS 3.1 | MEDIUM 5.4 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N | NVD · nvd@nist.gov (Primary) |
Advisories
- GHSA-4633-3j49-mh5q — Next.js: Cache confusion of response bodies for requests with bodies containing invalid UTF-8 byte sequences
European references
- ENISA EUVD · EUVD-2026-49404
- GCVE · GCVE-0-2026-64647
CERT-FR advisories
- CERTFR-2026-AVI-1291 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1256 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:a:vercel:next.js:*:*:*:*:*:node.js:*:*≥ 13.0.0 < 15.5.21cpe:2.3:a:vercel:next.js:*:*:*:*:*:node.js:*:*≥ 16.0.0 < 16.2.11
Affected products
| Product | Versions |
|---|---|
| vercel · next.js | affected >= 13.0.0, < 15.5.21 ; affected >= 16.0.0, < 16.2.11 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |