CVE-2026-41568

A flaw was found in the Moby container framework. A race condition during the docker cp mount setup allows a malicious container to create empty files or directories at arbitrary locations on the host filesystem. This vulnerability can lead to a denial of service by filling up disk space or interfering with critical system files.

This flaw is rated as Low impact. A race condition in the docker cp mount setup within the Moby container framework allows a malicious container to create empty files or directories at arbitrary locations on the host filesystem. Successful exploitation is difficult (AC:H) due to the timing-dependent nature of the race condition. Containers that do not have volume mounts are not affected, as the race occurs during volume bind-mount setup.

Denial of Service is possible by:

• Converting /etc/docker/daemon.json into a directory prevents the daemon from restarting
• Creating /etc/nologin prevents user logins
• Overwriting critical system paths with empty files can break host services

The container does not gain read or write access to existing host files — only the ability to create new empty files or directories at chosen paths.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Avoid using docker cp with untrusted running containers. Recommended to apply patches: Mountpoint creation is now scoped to the container root using os.Root (Go 1.24+), which refuses to follow symlinks that escape the opened root directory. All filesystem operations in createIfNotExists (MkdirAll, OpenFile) are performed through the os.Root handle, so even if a symlink swap occurs after path resolution, the creation stays confined to the container root.