Use of Cache Containing Sensitive Information Affecting next package, versions >=13.0.0 <15.5.21>=16.0.0 <16.2.11
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-JS-NEXT-18233146
- published23 Jul 2026
- disclosed22 Jul 2026
- creditrafabd1
Introduced: 22 Jul 2026
NewCVE-2026-64648 (opens in a new tab)How to fix?
Upgrade next to version 15.5.21, 16.2.11 or higher.
Overview
next is a react framework.
Affected versions of this package are vulnerable to Use of Cache Containing Sensitive Information in createPatchedFetcher in packages/next/src/server/lib/patch-fetch.ts. An attacker can leak a cached response body from one request to another by sending server-side fetch(new Request(...), init) calls to the same URL with different request bodies or overrides. When the Request object and the separate init object diverge, the fetch cache can key the request differently from the effective upstream request, so a response generated for one body is reused for a different body. This exposes confidential data in cached POST responses to unauthorized requests.
Notes
- Applications using the Pages Router are not in scope for this issue; the advisory applies to the server-side patched fetch path.
- The leak requires
fetch(new Request(...), init)where the separateinitoverrides the baseRequest;fetch(new Request(init), init)is the safe shape called out by the maintainers.