Critical · published August 13, 2026
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.
| Product | Versions | Fixed in |
|---|---|---|
| canonical/lxd | ≥ 5.0.0, < 5.0.8 | 5.0.8 |
| canonical/lxd | ≥ 5.1, < 5.21.6 | 5.21.6 |
| canonical/lxd | ≥ 6.0, < 6.9 | 6.9 |