GHSA-2m5v-pch6-74hx: undici (CVE-2026-109383)

Package	Ecosystem	Affected	Fixed in
undici	npm	>=4.0.0, <6.29.1 \|\| >=7.0.0, <7.30.1 \|\| >=8.0.0, <8.12.2	6.29.1, 7.30.1, 8.12.2

Machine-written summary

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

Undici versions 4.0.0 up to but not including 6.29.1, 7.0.0 up to but not including 7.30.1, and 8.0.0 up to but not including 8.12.2 are affected. When a caller passes a custom checkServerIdentity callback through the tls option of Agent, the JSON-based cloning drops the function, so a server whose certificate the callback should reject is accepted if it passes Node's default checks. Upgrade to undici 6.29.1, 7.30.1, or 8.12.2, which forward the tls option unchanged; if upgrading is not possible, pass TLS options through connect instead.

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
7.4	High	3.1	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N	CNA (openjs)

CISA KEV Not listed.
EPSS 0.0018, the 8th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

31 Oct 2026, 13:33 UTC First seen by agentprime
31 Oct 2026, 13:33 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.