An improper validation flaw in LXD’s instancePostMigration routine permits an authenticated user with can_create_instances privileges on a restricted project to create an instance that violates the target project’s configuration constraints and then move it into that project. The vulnerability lies in the failure to enforce restrictions such as restricted.containers.lowlevel, restricted.devices.*, and restricted.networks.access during migration, allowing the attacker to inject privileged resources that can execute commands on the host. The weakness is identified as CWE‑862, a failure in access control, and results in the attacker gaining full host command execution capability.

The issue affects Canonical’s LXD container manager. All releases prior to 5.0.8, 5.21.6, or 6.10 are vulnerable; upgrading to any of those versions or later eliminates the flaw.

The CVSS score of 9.9 indicates critical severity, and though an EPSS score is not available, the absence of mitigation means the risk is high. The attacker must be authenticated and possess can_create_instances rights on a restricted project, but once those conditions are met, the migration can be exploited with no external trigger. The vulnerability is not listed in CISA’s KEV catalog, but the high severity and potential for host compromise warrant immediate attention.