Critical severity · published Aug 12, 2026
CVE-2026-63297
Cross-project instance copy bypasses target project restrictions via TOCTOU in config merge
9.9
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 28% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LX
LXD · Canonical
5.0.0 before 5.0.8; 5.21.0 before 5.21.6 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-63297
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-63297
Vendor Advisory
https://github.com/canonical/lxd/security/advisories/GHSA-v989-qw7w-xvg4
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