CVE-2025-52881: runc container escape and denial of service due to arbitrary write gadgets and procfs write redirects

CVE-2025-52881 · Severity: high · CVSS 7.5 · Published 2025-11-06

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.

Technologies: github.com/opencontainers/runc (Go). Vendors: Go.

Quick answers

Is CVE-2025-52881 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2025-52881 being exploited in the wild.
How severe is CVE-2025-52881?
High severity, with a CVSS score of 7.5, published 6 November 2025.
Which products and versions are affected?
github.com/opencontainers/runc (Go) SEMVER:introduced=0,fixed=1.2.8, SEMVER:introduced=0,fixed=1.2.8,introduced=1.3.0-rc.1,fixed=1.3.3,introduced=1.4.0-rc.1,fixed=1.4.0-rc.3; github.com/opencontainers/selinux (Go) SEMVER:introduced=0,fixed=1.13.0.
Is there a fix for CVE-2025-52881?
Yes. github.com/opencontainers/runc (Go): upgrade to 1.2.8, 1.4.0-rc.3 or later; github.com/opencontainers/selinux (Go): upgrade to 1.13.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
Am I affected by CVE-2025-52881?
Check whether you run github.com/opencontainers/runc (Go) or github.com/opencontainers/selinux (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • github.com/opencontainers/runc (Go): upgrade to 1.2.8, 1.4.0-rc.3 or later
    go get github.com/opencontainers/runc@v1.4.0-rc.3
  • github.com/opencontainers/selinux (Go): upgrade to 1.13.0 or later
    go get github.com/opencontainers/selinux@v1.13.0

Affected products

  • github.com/opencontainers/runc (Go) SEMVER:introduced=0,fixed=1.2.8, SEMVER:introduced=0,fixed=1.2.8,introduced=1.3.0-rc.1,fixed=1.3.3,introduced=1.4.0-rc.1,fixed=1.4.0-rc.3
  • github.com/opencontainers/selinux (Go) SEMVER:introduced=0,fixed=1.13.0

Identifiers

  • CVE-2025-52881
  • GHSA-cgrx-mc8f-2prm
  • GO-2025-4098

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