CVE-2026-63297: Canonical LXD · Time-of-check Time-of-use (TOCTOU) Race Condition
Affects Canonical LXDSource CVE Database V5
Not known to be exploited · CVSS 9.9 Critical : upgrade to 5.21.6 or 5.0.8 as a priority.
Data as of 11 Nov 2026, 23:24 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 28% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.21.6, 5.0.8
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 12 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 12 Nov 2026.
What to do
Upgrade Canonical LXD to 5.21.6 or 5.0.8.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| CanonicalLXD | Affected
| Fixed in
|
| CanonicalLXD | Affected
| Fixed in
|
GitHubLXDpkg:github/LXDOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
If you cannot patch yet, administrators should exercise caution when performing cross-project instance copies and consider restricting such operations to trusted users only.
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.