Incus, a system container manager, has a flaw in project-level enforcement of the isolated container restriction. When the key 'security.idmap.isolated' is omitted, the default false value allows a user to create a non-isolated container even when the project disallows it. This bypass removes the expected tenant isolation, letting the container share the host UID/GID map and weakening the security boundary between the host and co-tenant containers. The vulnerability could be used by a user to access files or processes that should be isolated.

Incus version 7.2.x and earlier on all supported platforms. The flaw exists in any Incus installation before 7.3.0 where project restrictions are enabled. The impacted product is the Incus container manager from the lxc:incus vendor.

The CVSS score of 4.3 indicates a moderate severity, while the EPSS score is not provided and the vulnerability is not listed in CISA KEV. The flaw is exploitable via a local or authenticated project user who can create containers; no remote code execution or vulnerability exploitation conditions are required beyond having project access. Attackers can simply omit the key in a container creation request, so the risk is high for environments that rely on the isolation restriction for tenant security.