Vulnerability in Linuxfoundation Runc
CVE-2025-31133
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.008 (57.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 57th percentile — 57.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: +0.000
Affected products
- Linuxfoundation Runc — versions 1.4.0
- Opencontainers Runc — versions < 1.2.8, >= 1.3.0-rc.1, < 1.3.3, >= 1.4.0-rc.1, <= 1.4.0-rc.3
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/opencontainers/runc/security/advisories/GHSA-9493-h29p-rfm2 (Patch, Third Party Advisory, Mitigation)
- github.com/opencontainers/runc/commit/1a30a8f3d921acbbb6a4bb7e99da2c05f8d48522 (Patch)
- github.com/opencontainers/runc/commit/5d7b2424072449872d1cd0c937f2ca25f418eb66 (Patch)
- github.com/opencontainers/runc/commit/8476df83b534a2522b878c0507b3491def48db9f (Patch)
- github.com/opencontainers/runc/commit/db19bbed5348847da433faa9d69e9f90192bfa64 (Patch)
Frequently asked questions
- What is CVE-2025-31133?
- CVE-2025-31133 is a high-severity vulnerability in Linuxfoundation Runc, classified under UNIX Symbolic Link (Symlink) Following. CVSS score: 7.8/10. Published 2025-11-06.
- How severe is CVE-2025-31133?
- High severity. CVSS v3 base score is 7.8 out of 10.
- Is CVE-2025-31133 known to be exploited?
- 6 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.