Next.js: Cache confusion of response bodies for requests with bodies

## Impact 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`. Safe: `fetch(new Request(init), init)` Unsafe: `fetch(new Request(init), aDifferentInit)` ## Workarounds No workaround exists besides upgrading. Applications using Pages Router are not vulnerable.

Source published

22 Jul 2026 23:08:17 UTC

Source modified

10 Sep 2026 03:51:10 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V4 · 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

Publisher rating · MODERATE