CVE-2025-52881 — runc
Fix: opencontainers/runc@a41366eCVE-2025-52881 is a CWE-61 vulnerability in github.com/opencontainers/runc. 1 public exploit reference exists, so weaponization risk is real. A fix is available for github.com/opencontainers/runc — see the affected versions and patch details below.
runc: LSM labels can be bypassed with malicious config using dummy procfs files
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-52881.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
github.com/opencontainers/runc🐹github.com/opencontainers/selinux🐹github.com/opencontainers/runc🐹github.com/opencontainers/runcReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/opencontainers/runc | all versions | 1.2.8go get github.com/opencontainers/runc@v1.2.8 |
| 🐹Go | github.com/opencontainers/selinux | all versions | 1.13.0go get github.com/opencontainers/selinux@v1.13.0 |
| 🐹Go | github.com/opencontainers/runc | ≥ 1.3.0-rc.1&&< 1.3.3 | 1.3.3go get github.com/opencontainers/runc@v1.3.3 |
| 🐹Go | github.com/opencontainers/runc | ≥ 1.4.0-rc.1&&< 1.4.0-rc.3 | 1.4.0-rc.3go get github.com/opencontainers/runc@v1.4.0-rc.3 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/opencontainers/runc, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/opencontainers/runc to 1.2.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-52881 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-52881 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-52881. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Red Hat considers this as an Important flaw since the impact is limited to local attack with minimal privileges in order to jeopardize the environment.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Enterprise Linux 10 | podman-7:5.6.0-6.el10_1 | RHSA-2025:21220 |
| Red Hat Enterprise Linux 10 | buildah-2:1.41.6-1.el10_1 | RHSA-2025:22012 |
| Red Hat Enterprise Linux 10.0 Extended Update Support | buildah-2:1.39.5-1.el10_0 | RHSA-2025:21633 |
| Red Hat Enterprise Linux 10.0 Extended Update Support | podman-6:5.4.0-14.el10_0 | RHSA-2025:23347 |
| Red Hat Enterprise Linux 8 | container-tools:rhel8-8100020251112161627.afee755d | RHSA-2025:21232 |
| Red Hat Enterprise Linux 8 | container-tools:rhel8-8100020251215152642.afee755d | RHSA-2025:23543 |
| Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | container-tools:rhel8-8060020260422144418.ad008a3a | RHSA-2026:10703 |
| Red Hat Enterprise Linux 8.8 Telecommunications Update Service | container-tools:rhel8-8080020260226135022.63b34585 | RHSA-2026:4693 |
Frequently Asked Questions
Is CVE-2025-52881 in your dependencies?
O3 Security finds CVE-2025-52881 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.