CVE-2021-41091

Insufficiently restricted permissions on data directory in Docker Engine

MEDIUM
6.3
CVSS Score
Published: October 4, 2021 at 08:20 PM UTC
Updated: June 17, 2026 at 04:07 AM UTC
3 products affected across 3 vendorsFedoraMobyMoby

Using moby by moby?

Get instant alerts when new vulnerabilities affect moby - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Severity
MEDIUM6.3
Exploit prediction
EPSS 3%

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 20.10.9
Affected range stops below 20.10.9, so it looks safe — our inference, not a vendor statement
v < 20.10.9
Affected range stops below 20.10.9, so it looks safe — our inference, not a vendor statement

CVSS

6.3MEDIUMGitHub_M
Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality
LOW
Integrity
LOW
Availability
LOW
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-281CWE-732

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Free plan, no card