CVE-2026-63297 CRITICAL

CVE-2026-63297: Cross-project instance copy bypasses target project restrictions via TOCTOU in config merge

Vendor Canonical
Product LXD
Weakness CWE-367
Published August 12, 2026
Last update August 12, 2026

CVSS base score

9.9/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality High
Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

August 12, 2026 CVE published