What is CVE-2023-25809?

CVE-2023-25809 is a medium-severity vulnerability in Linuxfoundation Runc, classified under Improper Preservation of Permissions. CVSS score: 5.0/10. Published 2023-03-29.

How severe is CVE-2023-25809?

Medium severity. CVSS v3 base score is 5.0 out of 10.

Is CVE-2023-25809 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Linuxfoundation Runc

CVE-2023-25809

runc is a CLI tool for spawning and running containers according to the OCI specification. In affected versions it was found that rootless runc makes `/sys/fs/cgroup` writable in following conditons: 1. when runc is executed inside the user namespace, and the `config.json` does not specify the cgroup namespace to be unshared (e.g.., `(docker|podman|nerdctl) run --cgroupns=host`, with Rootless Docker/Podman/nerdctl) or 2. when runc is executed outside the user namespace, and `/sys` is mounted with `rbind, ro` (e.g., `runc spec --rootless`; this condition is very rare). A container may gain the write access to user-owned cgroup hierarchy `/sys/fs/cgroup/user.slice/...` on the host . Other users's cgroup hierarchies are not affected. Users are advised to upgrade to version 1.1.5. Users unable to upgrade may unshare the cgroup namespace (`(docker|podman|nerdctl) run --cgroupns=private)`. This is the default behavior of Docker/Podman/nerdctl on cgroup v2 hosts. or add `/sys/fs/cgroup` to `maskedPaths`.

Published 2023-03-29 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.0 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:L/I:L/A:L.

EPSS exploit prediction

EPSS: 0.003 (23.4th percentile), scored 2026-10-21.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 23rd percentile — 23.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Linuxfoundation Runc
Opencontainers Runc — versions < 1.1.5

Weakness classification (CWE)

CWE-281 — Improper Preservation of Permissions

Public proof-of-concept exploits

8-cm/kube-dump

References

github.com/opencontainers/runc/security/advisories/GHSA-m8cg-xc2p-r3fc (Exploit, Vendor Advisory)
github.com/opencontainers/runc/commit/0d62b950e60f6980b54fe3bafd9a9c608dc1df17 (Patch)

Frequently asked questions

What is CVE-2023-25809?: CVE-2023-25809 is a medium-severity vulnerability in Linuxfoundation Runc, classified under Improper Preservation of Permissions. CVSS score: 5.0/10. Published 2023-03-29.
How severe is CVE-2023-25809?: Medium severity. CVSS v3 base score is 5.0 out of 10.
Is CVE-2023-25809 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.