CVE-2021-41103

Insufficiently restricted permissions on plugin directories

Published Oct 4, 2021 CVSS 3.1 · 7.8 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DSA Debian DSA DSA-5002-1 containerd security update
EUVD EUVD EUVD-2021-2187 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.
Github GHSA Github GHSA GHSA-c2h3-6mxw-7mvq Insufficiently restricted permissions on plugin directories
Ubuntu USN Ubuntu USN USN-5100-1 containerd vulnerability
Ubuntu USN Ubuntu USN USN-5521-1 containerd vulnerabilities
History

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Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Aug 4, 2024, 2:59 AM
Reserved
Sep 15, 2021, 12:00 AM
Status
Modified
Published
Oct 4, 2021, 5:15 PM
Modified
Jun 17, 2026, 4:07 AM
Severity
Moderate
Public date
Oct 4, 2021, 12:00 AM