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CVE-2026-64647

Next.js: Response Body Cache Confusion with Invalid UTF-8 Request Bodies

Published: Jul 27, 2026Updated: Jul 29, 2026 Sources: CVE List NVDCWE-116
5.4MEDIUM
NVD MITRE
EPSS Score
0.3%
Top 73.6%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
OpenVAS

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:RS:UC:LI:LA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:RUser Interaction
Required
Scope
S:UScope
Unchanged
Impact
C:LConfidentiality
Low
I:LIntegrity
Low
A:NAvailability
None
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Weaknesses

CWE-116

Affected Products

vercel
commercial·US
next.jsLibraryLibrary
OSS Libraries / web-framework

Exploitability

Official Patch Available
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References

https://github.com/vercel/next.js/security/advisories/GHSA-4633-3j49-mh5q
github.com
https://github.com/vercel/next.js/pull/96008
github.com
https://github.com/vercel/next.js/commit/025bf4a5f7b47fb7758c4ebf1c931a61c451c082
github.com
and 2 more references View all →

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