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.
Advisories
| Source | ID | Title |
|---|---|---|
Github GHSA |
GHSA-4633-3j49-mh5q | Next.js: Cache confusion of response bodies for requests with bodies containing invalid UTF-8 byte sequences |
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Tue, 28 Jul 2026 04:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Vercel
Vercel next.js |
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| Vendors & Products |
Vercel
Vercel next.js |
Mon, 27 Jul 2026 20:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | Next.js: Response Body Cache Confusion with Invalid UTF-8 Request Bodies | |
| Weaknesses | CWE-116 | |
| References |
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| Metrics |
cvssV4_0
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Projects
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-07-27T19:27:13.932Z
Reserved: 2026-07-20T17:11:30.895Z
Link: CVE-2026-64647
Updated: 2026-07-27T19:27:11.150Z
No data.
No data.
OpenCVE Enrichment
Updated: 2026-07-28T04:15:04Z
Weaknesses
Github GHSA