What is CVE-2021-41089?

CVE-2021-41089 is a low-severity vulnerability in Moby, classified under Improper Preservation of Permissions. CVSS score: 2.8/10. Published 2021-10-04.

How severe is CVE-2021-41089?

Low severity. CVSS v3 base score is 2.8 out of 10.

Is CVE-2021-41089 known to be exploited?

4 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Moby

CVE-2021-41089

Moby is an open-source project created by Docker to enable software containerization. A bug was found in Moby (Docker Engine) where attempting to copy files using `docker cp` into a specially-crafted container can result in Unix file permission changes for existing files in the host’s filesystem, widening access to others. This bug does not directly allow files to be read, modified, or executed without an additional cooperating process. This bug has been fixed in Moby (Docker Engine) 20.10.9. Users should update to this version as soon as possible. Running containers do not need to be restarted.

Published 2021-10-04 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 2.8 (Low). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.003 (19.4th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 19th percentile — 19.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Moby — versions < 20.10.9
Mobyproject Moby
Fedoraproject Fedora — versions 34, 35

Weakness classification (CWE)

CWE-281 — Improper Preservation of Permissions

Public proof-of-concept exploits

References

github.com/moby/moby/security/advisories/GHSA-v994-f8vw-g7j4 (Third Party Advisory)
github.com/moby/moby/commit/bce32e5c93be4caf1a592582155b9cb837fc129a (Patch, Third Party Advisory)
lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
cert-portal.siemens.com/productcert/pdf/ssa-222547.pdf

Frequently asked questions

What is CVE-2021-41089?: CVE-2021-41089 is a low-severity vulnerability in Moby, classified under Improper Preservation of Permissions. CVSS score: 2.8/10. Published 2021-10-04.
How severe is CVE-2021-41089?: Low severity. CVSS v3 base score is 2.8 out of 10.
Is CVE-2021-41089 known to be exploited?: 4 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.