A bug was found in containerd where container root directories and some plugins had insufficiently restricted permissions, allowing otherwise unprivileged Linux users to traverse directory contents and execute programs. When containers included executable programs with extended permission bits (such as setuid), unprivileged Linux users could discover and execute those programs. When the UID of an unprivileged Linux user on the host collided with the file owner or group inside a container, the unprivileged Linux user on the host could discover, read, and modify those files.
This vulnerability has been fixed in containerd 1.4.11 and containerd 1.5.7. Users should update to these version when they are released and may restart containers or update directory permissions to mitigate the vulnerability.
Limit access to the host to trusted users. Update directory permission on container bundles directories.
If you have any questions or comments about this advisory:
cert-portal.siemens.com/productcert/pdf/ssa-222547.pdf
github.com/containerd/containerd
github.com/containerd/containerd/commit/5b46e404f6b9f661a205e28d59c982d3634148f8
github.com/containerd/containerd/releases/tag/v1.4.11
github.com/containerd/containerd/releases/tag/v1.5.7
github.com/containerd/containerd/security/advisories/GHSA-c2h3-6mxw-7mvq
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/B5Q6G6I4W5COQE25QMC7FJY3I3PAYFBB
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZNFADTCHHYWVM6W4NJ6CB4FNFM2VMBIB
lists.fedoraproject.org/archives/list/[email protected]/message/B5Q6G6I4W5COQE25QMC7FJY3I3PAYFBB
lists.fedoraproject.org/archives/list/[email protected]/message/ZNFADTCHHYWVM6W4NJ6CB4FNFM2VMBIB
nvd.nist.gov/vuln/detail/CVE-2021-41103
security.gentoo.org/glsa/202401-31
www.debian.org/security/2021/dsa-5002