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 only applies to fetch calls with a request that has a different init than the one passed to fetch. A safe request would be: fetch(new Request(init), init). An unsafe request would be: fetch(new Request(init), aDifferentInit). This issue has been fixed in versions 15.5.21 and 16.2.11.
History

Wed, 29 Jul 2026 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N'}

threat_severity

Important


Tue, 28 Jul 2026 16:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Tue, 28 Jul 2026 05:00:00 +0000

Type Values Removed Values Added
First Time appeared Vercel
Vercel next.js
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 only applies to fetch calls with a request that has a different init than the one passed to fetch. A safe request would be: fetch(new Request(init), init). An unsafe request would be: fetch(new Request(init), aDifferentInit). This issue has been fixed in versions 15.5.21 and 16.2.11.
Title Next.js: Response Body Cache Confusion for Requests Containing Bodies
Weaknesses CWE-524
References
Metrics cvssV4_0

{'score': 6, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-07-27T19:20:42.623Z

Updated: 2026-07-28T14:14:16.051Z

Reserved: 2026-07-20T17:11:30.895Z

Link: CVE-2026-64648

cve-icon Vulnrichment

Updated: 2026-07-28T14:14:08.569Z

cve-icon NVD

No data.

cve-icon Redhat

Severity : Important

Publid Date: 2026-07-27T19:20:42Z

Links: CVE-2026-64648 - Bugzilla