GHSA-xp26-3454-mjgp: @vitest/mocker (CVE-2026-112950)

Package	Ecosystem	Affected	Fixed in
@vitest/mocker	npm	>=4.1.11, <4.1.12 \|\| >=5.0.0-rc.2, <5.0.3	4.1.12, 5.0.3

Machine-written summary

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

Vitest's @vitest/mocker is vulnerable on Windows in versions >=4.1.11 <4.1.12 and >=5.0.0-rc.2 <5.0.3, where a backslash in a redirect URL pathname bypasses the allowlist fix for GHSA-82fw-gwwq-j7x9 and lets a client read a file outside the Vite root. Per the source, an attacker needs network reach to a Vite server using the public mockerPlugin or interceptorPlugin WebSocket registration, and default loopback-only servers are less exposed. Upgrade to @vitest/mocker 4.1.12 or 5.0.3, which are listed as fixed.

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
5.9	Medium	3.1	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N	CNA (GitHub_M)

CISA KEV Not listed.
EPSS 0.0054, the 45th percentile, on 6 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.