Incus, a system container and VM manager, allows users who can launch containers with custom images to use directory traversal or symbolic links in the templating mechanism, resulting in arbitrary file read and write on the host. This flaw, which is a case of CWE‑22 Path Traversal, can be leveraged to execute commands on the host, compromising confidentiality, integrity, and availability at the system level.

The vulnerability affects the LinuxContainers Incus product, versions 6.21.0 and earlier, including IncusOS deployments. The flaw is present when an image contains a metadata.yaml file with template definitions that are not validated for traversal or symlink usage.

The assigned CVSS score of 8.7 indicates a high severity. The EPSS score is below 1%, suggesting low current exploitation probability, and the vulnerability is not listed in CISA’s KEV catalog. Exploitation requires local access to start a container and membership in the incus group, and involves crafting a template image that points to arbitrary host paths. Attackers who can meet these conditions can read sensitive files or overwrite critical configuration, leading to arbitrary command execution on the host.