GHSA-9493-h29p-rfm2: github.com/opencontainers/runc (CVE-2025-31133)

Package	Ecosystem	Affected	Fixed in
github.com/opencontainers/runc	Go	<1.2.8 \|\| >=1.3.0-rc.1, <1.3.3 \|\| >=1.4.0-rc.1, <1.4.0-rc.3	1.2.8, 1.3.3, 1.4.0-rc.3

Machine-written summary

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

Versions of the Go package github.com/opencontainers/runc before 1.2.8, from 1.3.0-rc.1 before 1.3.3, and from 1.4.0-rc.1 before 1.4.0-rc.3 are affected. An attacker who can start containers with shared mounts, such as through a parallel build, can race the runtime's handling of /dev/null so that a bind mount targets an arbitrary host path, which can lead to host denial of service or container escape, or let them bypass maskedPaths. Upgrade to runc 1.2.8, 1.3.3, 1.4.0-rc.3 or later.

Written 1 Nov 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
7.3	High	4.0	CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H	CNA (GitHub_M)

CISA KEV Not listed.
EPSS 0.012, the 69th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

31 Oct 2026, 14:14 UTC First seen by agentprime
31 Oct 2026, 14:14 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.