GHSA-8436-99hf-9mmv: undici (CVE-2026-85008)

Package	Ecosystem	Affected	Fixed in
undici	npm	>=7.0.0, <7.29.1 \|\| >=8.0.0, <8.10.2	7.29.1, 8.10.2

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Undici versions 7.0.0 up to but not including 7.29.1, and 8.0.0 up to but not including 8.10.2, have a bug in the cache interceptor where responses to unsafe HTTP methods (POST, PUT, PATCH, DELETE) can be stored and later served from cache instead of reaching the origin. An attacker who controls an origin server can trigger this through the origin's own response headers, with no application misuse needed, and the cached fabricated response can then be returned in place of a state-changing request's result. Upgrade to undici 7.29.1 or 8.10.2; the source lists no workarounds.

Written 31 Oct 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
3.7	Low	3.1	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N	CNA (openjs)

CISA KEV Not listed.
EPSS 0.0012, the 1st percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

31 Oct 2026, 13:34 UTC First seen by agentprime
31 Oct 2026, 13:34 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.