CVE-2025-52881

High

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.

SeverityHigh
CVSS7.5
Exploit probability—
ProductLinuxfoundation Runc
PublishedNov 6, 2025
First seenNov 6, 2025

How to fix

Update
  • linuxfoundation runc1.2.8, 1.3.3 or later
  • github.com/opencontainers/runc1.2.8, 1.3.3, 1.4.0-rc.3 or later
  • github.com/opencontainers/selinux1.13.0 or later

Affected products

ProductAffected versionsFixed in
linuxfoundation runcv < 1.2.8, 1.3.0 ≤ v < 1.3.3, 1.4.01.2.8, 1.3.3
github.com/opencontainers/runcGov < 1.2.8, 1.3.0-rc.1 ≤ v < 1.3.3, 1.4.0-rc.1 ≤ v < 1.4.0-rc.31.2.8, 1.3.3, 1.4.0-rc.3
github.com/opencontainers/selinuxGov < 1.13.01.13.0

Check your version

Choose the product and enter the version you run to see whether it falls in the affected range.

In the Intelligence 360 plan

Attack Surface Management

See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.

CVE-2025-52881 · Linuxfoundation Runc · Dark Radar