CVE-2026-63297: Canonical Lxd

Critical severity, CVSS 9.9. EPSS: 0.3% chance of exploitation in the next 30 days.

An authorization bypass vulnerability in LXD due to a timing flaw during configuration merging allows an authenticated attacker to bypass target project restrictions during cross-project instance copies. When copying an instance to a target project, LXD performs restriction checks before configuration merging is complete, creating a time-of-check to time-of-use (TOCTOU) condition. An attacker can exploit this flaw to copy instances with disallowed high-privilege configurations into restricted projects, bypassing security controls.

Affected products

• Canonical Lxd: from 5.0.0, before 5.0.8 (fixed in 5.0.8); from 5.1, before 5.21.6 (fixed in 5.21.6); from 6.0, before 6.9 (fixed in 6.9)

Published 2026-08-12. Last modified 2026-09-11.