Vulnerability · Published Aug 12, 2026 · Assigned by canonical
CVE-2026-63297Cross-project instance copy bypasses target project restrictions via TOCTOU in config merge
Critical 9.9
In plain English
A critical-severity incorrect authorization in LXD from Canonical. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 28% of all known vulnerabilities).
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | lxd | no fix listed | DEBIAN-CVE-2026-63297 |
| Debian:13 | lxd | no fix listed | DEBIAN-CVE-2026-63297 |
Affected products (as reported)
Weakness: CWE-367, CWE-863 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
References
- https://github.com/canonical/lxd/security/advisories/GHSA-v989-qw7w-xvg4 vdb-entry, vendor-advisory