CVE-2023-25809
Rootless: /sys/fs/cgroup is writable when cgroupns isn't unshared in github.com/opencontainers/runc
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`.
How to fix CVE-2023-25809
To remediate CVE-2023-25809, upgrade the affected package to a fixed version below.
- —upgrade to 1.0.0~rc93+ds1-5+deb11u4 or later
- —upgrade to 1.1.5 or later
- —upgrade to 1.1.5 or later
Is CVE-2023-25809 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (3)
- from 0, < 1.0.0~rc93+ds1-5+deb11u4
- from 0, < 1.1.5
- from 0, < 1.1.5
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | LOW2.5 | CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:N/I:N/A:L |