CVE-2023-25809
rootless: `/sys/fs/cgroup` is writable when cgroupns isn't unshared in runc
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
Description
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`.
Timeline
ID reserved
By GitHub_M
- 42 days later
· 42 days later
Published
- 23 months later
· 23 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | Medium5.0 | CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:L/I:L/A:L |
| NVDNVD · Modified | 3.1 | Medium6.3 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:L |
- EPSS (exploitation in 30 days)
- 0.32% · top 75% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.0.
Weakness
Affected products
- affected < 1.1.5
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- Gogithub.com/opencontainers/runcGHSA-m8cg-xc2p-r3fc (opens in a new tab)
References (2)
- https://github.com/opencontainers/runc/security/advisories/GHSA-m8cg-xc2p-r3fc (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://github.com/opencontainers/runc/commit/0d62b950e60f6980b54fe3bafd9a9c608dc1df17 (opens in a new tab)x_refsource_MISCx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-m8cg-xc2p-r3fc (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2023-25809)Record last updated .