CVE-2025-31133
Container escape via "masked path" abuse due to mount race conditions in github.com/opencontainers/runc
Description
runc is a CLI tool for spawning and running containers according to the OCI specification. In versions 1.2.7 and below, 1.3.0-rc.1 through 1.3.1, 1.4.0-rc.1 and 1.4.0-rc.2 files, runc would not perform sufficient verification that the source of the bind-mount (i.e., the container's /dev/null) was actually a real /dev/null inode when using the container's /dev/null to mask. This exposes two methods of attack: an arbitrary mount gadget, leading to host information disclosure, host denial of service, container escape, or a bypassing of maskedPaths. This issue is fixed in versions 1.2.8, 1.3.3 and 1.4.0-rc.3.
How to fix CVE-2025-31133
To remediate CVE-2025-31133, upgrade the affected package to a fixed version below.
- —no fix listed
- —upgrade to 1.2.8 or later
- —upgrade to 1.2.8 or later
Is CVE-2025-31133 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (3)
- from 0
- from 0, < 1.2.8
- from 0, < 1.2.8, >= 1.3.0-rc.1, < 1.3.3, >= 1.4.0-rc.1, < 1.4.0-rc.3
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 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 |
| osv | CVSS 3.1 | HIGH7.8 | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H |