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`.

• How can I get the fixes?
• What do statuses mean?

References

• MITRE
• NVD
• Launchpad
• Debian

Related Ubuntu Security Notices (USN)

• USN-6088-1
• runC vulnerabilities
• 18 May 2023
• USN-6088-2
• runC vulnerabilities
• 23 May 2023

Other references

• https://github.com/opencontainers/runc/security/advisories/GHSA-m8cg-xc2p-r3fc
• https://github.com/opencontainers/runc/commit/0e6b818a2b0d24fdb6697614e5c5f115bbe8e3a5 (v1.1.5)
• https://www.cve.org/CVERecord?id=CVE-2023-25809