Vulnerability details

CVE-2025-52881

opencontainers runc

runc: LSM labels can be bypassed with malicious config using dummy procfs files

CVSS 4.0
7.3High

Official description

runc is a CLI tool for spawning and running containers according to the OCI specification. In versions 1.2.7, 1.3.2 and 1.4.0-rc.2, an attacker can trick runc into misdirecting writes to /proc to other procfs files through the use of a racing container with shared mounts (we have also verified this attack is possible to exploit using a standard Dockerfile with docker buildx build as that also permits triggering parallel execution of containers with custom shared mounts configured). This redirect could be through symbolic links in a tmpfs or theoretically other methods such as regular bind-mounts. While similar, the mitigation applied for the related CVE, CVE-2019-19921, was fairly limited and effectively only caused runc to verify that when LSM labels are written they are actually procfs files. This issue is fixed in versions 1.2.8, 1.3.3, and 1.4.0-rc.3.

CVSS scores

ScoreVersionSourceVector
7.3High 4.0 CVEProject cvelistV5 (CNA) (GitHub_M) 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

Affected products

VendorProductVersionsSource
opencontainers runc <= 1.2.7, < 1.2.8 CVEProject cvelistV5 (CNA)
opencontainers runc <= 1.3.2, < 1.3.3 CVEProject cvelistV5 (CNA)
opencontainers runc <= 1.4.0-rc.2, < 1.4.0-rc.3 CVEProject cvelistV5 (CNA)

References and advisories

20
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Details

Published
2025-11-06
Last updated
2025-11-07
State
Published
Assigner (CNA)
GitHub_M

Exploit prediction (EPSS)

0.8%
Probability of exploitation in 30 days
56.8%
Percentile (among all CVEs)

SSVC assessment (CISA)

Automatable
No
Exploitation
None
Technical impact
Total

Weaknesses (CWE)

  • CWE-61
    UNIX Symbolic Link (Symlink) Following
  • CWE-363
    Race Condition Enabling Link Following