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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
SUSE Affected 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Affected | — |
Arch Fixed 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Fixed | 1:20.10.9-1 |
Debian Fixed 5 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Fixed | 20.10.10+dfsg1-1 |
| sid | Fixed | 20.10.10+dfsg1-1 |
| forky | Fixed | 20.10.10+dfsg1-1 |
| bullseye | Fixed | 20.10.5+dfsg1-1+deb11u1 |
| bookworm | Fixed | 20.10.10+dfsg1-1 |
Package impact
| Ecosystem | Package | Vulnerable | Fixed |
|---|---|---|---|
| Go | github.com/docker/docker | <20.10.9 | 20.10.9 |
| Go | github.com/moby/moby | <20.10.9 | 20.10.9 |
| Go | github.com/docker/docker | <20.10.9+incompatible | 20.10.9+incompatible |
| Go | github.com/moby/moby | <20.10.9+incompatible | 20.10.9+incompatible |
References
- https://security-tracker.debian.org/tracker/CVE-2021-41091
- https://www.suse.com/security/cve/CVE-2021-41091.html
- https://github.com/moby/moby/security/advisories/GHSA-3fwx-pjgw-3558
- https://nvd.nist.gov/vuln/detail/CVE-2021-41091
- https://github.com/moby/moby/commit/f0ab919f518c47240ea0e72d0999576bb8008e64
- https://cert-portal.siemens.com/productcert/pdf/ssa-222547.pdf
- https://github.com/moby/moby
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/B5Q6G6I4W5COQE25QMC7FJY3I3PAYFBB
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ZNFADTCHHYWVM6W4NJ6CB4FNFM2VMBIB
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.