Incus versions before 7.3.0 have an incorrect authorization flaw where the project-level enforcement of the 'restricted.containers.privilege=isolated' setting can be bypassed. The enforcement mechanism only rejects an explicitly set 'security.idmap.isolated=false' or empty value but does not enforce restrictions when the key is omitted. Since the default for an unset 'security.idmap.isolated' is false (non-isolated), a user can omit this key to create a container that shares the host UID/GID map, defeating the intended tenant isolation. This vulnerability compromises the isolation boundary between co-tenant containers and the host. The issue is resolved in Incus version 7.3.0.

The vulnerability allows users to create containers that share the host UID/GID map in projects that are configured to enforce isolated container privileges. This weakens the isolation guarantees between containers and the host, potentially increasing the risk of privilege escalation or unauthorized access within multi-tenant environments. However, the CVSS score of 4.3 and the absence of known exploits in the wild indicate a medium severity impact with limited immediate exploitation risk.

Upgrade Incus to version 7.3.0 or later, where this authorization bypass issue is patched. No other mitigations are indicated by the vendor advisory. Patch status is not explicitly stated but the description confirms the issue is fixed in 7.3.0.