CVE-2021-41103 Insufficiently restricted permissions on plugin directories

What is CVE-2021-41103?

CVE-2021-41103 is a medium-severity missing authorization vulnerability in Debian Debian Linux, published on 4 Oct 2021. It can only be exploited from the same machine or local network, with no action from the victim.

Official 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.

Weakness: CWE-22

Which versions are affected by CVE-2021-41103?

5 open source packages ship an affected version, including github.com/containerd/containerd. It affects 3 products.

Products include Debian Debian Linux, Fedoraproject Fedora, Linuxfoundation Containerd.

How do I fix CVE-2021-41103?

Upgrade github.com/containerd/containerd to a fixed version for your release line: 1.4.11 or 1.5.7.

Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is CVE-2021-41103 being exploited?

There is no known exploitation of CVE-2021-41103 in the wild and no public exploit code.

Other vulnerabilities in Debian Debian Linux

• CVE-2015-3306 ProFTPD Improper Access Control Exploited Critical 10.0
• CVE-2025-49113 RoundCube Webmail Deserialization of Untrusted Data Exploited Critical 9.9
• CVE-2026-24061 GNU InetUtils Argument Injection Exploited Critical 9.8
• CVE-2025-39682 Linux Kernel Improper Check for Unusual or Exceptional Conditions Exploited Critical 9.8
• CVE-2024-9680 Mozilla Firefox Use-After-Free Exploited Critical 9.8

All Debian Debian Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as AZL-6681, CLEANSTART-2025-SC08629, DEBIAN-CVE-2021-41103, DSA-5002-1, GHSA-c2h3-6mxw-7mvq, GO-2022-0938 and 4 more.