CVE-2026-63297

Critical

Description

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.

SeverityCritical
CVSS9.9
Exploit probability—
ProductCanonical Lxd
PublishedAug 12, 2026
First seenAug 12, 2026

How to fix

Update
  • canonical lxd5.0.8, 5.21.6, 6.9 or later

Affected products

ProductAffected versionsFixed in
canonical lxd5.0.0 ≤ v < 5.0.8, 5.1 ≤ v < 5.21.6, 6.0 ≤ v < 6.95.0.8, 5.21.6, 6.9

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