What is CVE-2026-63297?

CVE-2026-63297 is a critical-severity vulnerability in Canonical Lxd, classified under Time-of-check Time-of-use (TOCTOU) Race Condition. CVSS score: 9.9/10. Published 2026-08-12.

How severe is CVE-2026-63297?

Critical severity. CVSS v3 base score is 9.9 out of 10.

Auth bypass in Canonical Lxd

CVE-2026-63297

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 targe…

Vulnerability class: TOCTOU (Time-of-Check to Time-of-Use)

CVSS v3 metric

CVSS v3 base score 9.9 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.

Affected products

Canonical Lxd — versions 5.0.0, 5.21.0

Weakness classification (CWE)

CWE-367 — Time-of-check Time-of-use (TOCTOU) Race Condition
CWE-863 — Incorrect Authorization

References

security@ubuntu.com (vendor-advisory, vdb-entry)

Frequently asked questions

What is CVE-2026-63297?: CVE-2026-63297 is a critical-severity vulnerability in Canonical Lxd, classified under Time-of-check Time-of-use (TOCTOU) Race Condition. CVSS score: 9.9/10. Published 2026-08-12.
How severe is CVE-2026-63297?: Critical severity. CVSS v3 base score is 9.9 out of 10.