Vulnerability Description
An improper validation vulnerability in the instancePostMigration function in lxd/instance_post.go of LXD allows an authenticated attacker with can_create_instances permissions on a restricted project to bypass project-level security restrictions. When migrating an instance between projects, LXD fails to validate the instance's configuration against the target project's enforced restrictions (such as restricted.containers.lowlevel, restricted.devices.*, and restricted.networks.access). An attacker can exploit this by creating a disallowed or high-privilege instance in an unrestricted project and subsequently moving it into the restricted project.
CVSS Score
CRITICAL
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Canonical | Lxd | >= 5.0.0, < 5.0.8 |
Related Weaknesses (CWE)
References
- https://github.com/canonical/lxd/pull/18605ExploitPatch
- https://github.com/canonical/lxd/pull/18651Patch
- https://github.com/canonical/lxd/security/advisories/GHSA-5g5r-wh97-qcq2Vendor AdvisoryExploitMitigation
FAQ
What is CVE-2026-63300?
CVE-2026-63300 is a vulnerability with a CVSS score of 9.9 (CRITICAL). An improper validation vulnerability in the instancePostMigration function in lxd/instance_post.go of LXD allows an authenticated attacker with can_create_instances permissions on a restricted project...
How severe is CVE-2026-63300?
CVE-2026-63300 has been rated CRITICAL with a CVSS base score of 9.9/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-63300?
Check the references section above for vendor advisories and patch information. Affected products include: Canonical Lxd.