GHSA-8436-99hf-9mmv
undici vulnerable to caching and replay of unsafe HTTP method responses
Quick fix
GHSA-8436-99hf-9mmv — undici: upgrade to the fixed version with the command below.
npm install undici@7.29.1Details
### Impact
undici's `interceptors.cache()` documents that it caches only safe HTTP methods. However, its internal skip-list is built by subtracting the configured methods from the safe-methods set, so an unsafe method (`POST`, `PUT`, `PATCH`, `DELETE`) never lands in the skip-list and is looked up against the cache store. Combined with the storage gate (`canCacheResponse`) having no method check, a heuristically-cacheable response (for example a `404`) with an explicit `Cache-Control: max-age=...` to an unsafe method is stored and replayed on a subsequent identical request. The application's state-changing request never reaches the origin, and undici serves a fabricated response from the cache instead. This occurs with the default configuration (`methods: ['GET']`), which the public API does not allow widening to unsafe methods, so no application misuse is required; an untrusted origin can trigger it purely through its own response headers.
### Patches
Upgrade to `7.29.1` or `8.10.2`. The cache interceptor no longer reads from or writes to the cache for unsafe HTTP methods, while still invalidating existing cache entries on successful unsafe requests.
### Workarounds
None.
Are you affected?
Enter the version of the package you're using.
Affected packages
References
- https://github.com/nodejs/undici/security/advisories/GHSA-8436-99hf-9mmv[WEB]
- https://nvd.nist.gov/vuln/detail/CVE-2026-85008[ADVISORY]
- https://github.com/nodejs/undici/commit/2be07bf97b3022e0324142d31f99f6e019d815e3[WEB]
- https://github.com/nodejs/undici/commit/b61d9432bac7caac51273ad209862e4c0bf935ae[WEB]
- https://cna.openjsf.org/security-advisories.html[WEB]
- https://github.com/nodejs/undici[PACKAGE]
- https://github.com/nodejs/undici/releases/tag/v7.29.1[WEB]
- https://github.com/nodejs/undici/releases/tag/v8.10.2[WEB]