Incus contains a restriction bypass flaw that lets users assigned to restricted projects, if they also have rights to create instances, trigger a cluster‑refresh migration on an existing instance. The resulting refresh request forces the server to open outbound TLS websocket connections, which can be used to probe or communicate with services reachable from the host. This vulnerability does not grant arbitrary code execution but enables attackers to perform internal network reconnaissance or potentially interact with services they would otherwise be unable to reach from within the restricted project. The weakness is identified as CWE‑863, an improper authorization control flaw.

The vulnerability affects Linux Containers Incus versions 6.0.5 through 6.0.6, 6.12.0 through 7.0.1, and 7.1.0 through 7.4.99. Any environment running a vulnerable Incus instance and configured for clustered migration is susceptible.

The CVSS score of 5.3 categorises the issue as medium severity. The EPSS score is not available, and the vulnerability is not listed in the CISA KEV catalogue, suggesting no current known widespread exploitation. However, exploitation requires an attacker to possess instance‑creation rights and to target a specific instance with a refresh request. If the cluster elects a node to perform the migration, it will establish outbound TLS websocket connections, potentially exposing the host to unintended network traffic. The attack vector is therefore internal to the cluster but may expose internal services to an attacker's control.