CVE-2021-41091

Name	CVE-2021-41091
Description	Moby is an open-source project created by Docker to enable software containerization. A bug was found in Moby (Docker Engine) where the data directory (typically `/var/lib/docker`) contained subdirectories with 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 bug has been fixed in Moby (Docker Engine) 20.10.9. Users should update to this version as soon as possible. Running containers should be stopped and restarted for the permissions to be fixed. For users unable to upgrade limit access to the host to trusted users. Limit access to host volumes to trusted containers.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
docker.io (PTS)	buster, buster (security)	18.09.1+dfsg1-7.1+deb10u3	vulnerable
	bullseye	20.10.5+dfsg1-1+deb11u2	fixed
	bookworm	20.10.24+dfsg1-1	fixed
	sid, trixie	20.10.25+dfsg1-2	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
docker.io	source	bullseye	20.10.5+dfsg1-1+deb11u1
docker.io	source	(unstable)	20.10.10+dfsg1-1

Notes

[buster] - docker.io <no-dsa> (Minor issue)
https://github.com/moby/moby/security/advisories/GHSA-3fwx-pjgw-3558
https://github.com/moby/moby/commit/f0ab919f518c47240ea0e72d0999576bb8008e64