CVE-2021-41103 Information

Description

containerd is an open source container runtime with an emphasis on simplicity robustness and portability. 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. Users unable to update should limit access to the host to trusted users. Update directory permission on container bundles directories.

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Reference

https://github.com/containerd/containerd/commit/5b46e404f6b9f661a205e28d59c982d3634148f8 https://github.com/containerd/containerd/security/advisories/GHSA-c2h3-6mxw-7mvq https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ZNFADTCHHYWVM6W4NJ6CB4FNFM2VMBIB/ https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/B5Q6G6I4W5COQE25QMC7FJY3I3PAYFBB/ https://www.debian.org/security/2021/dsa-5002

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

HIGH

Availability Impact

HIGH

Base Score

HIGH

Base Severity

7.8