Cross-project instance copy bypasses target project restrictions via TOCTOU in config merge

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-63297
StatePUBLISHED
Assignercanonical
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-12 20:17:47 UTC
Updated2026-08-13 15:19:54 UTC
DescriptionAn 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.

Risk And Classification

Primary CVSS: v3.1 9.9 CRITICAL from [email protected]

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

EPSS: 0.001960000 probability, percentile 0.096200000 (date 2026-08-13)

Problem Types: CWE-367 | CWE-863 | CWE-367 CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition | CWE-863 CWE-863 Incorrect Authorization

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary9.9CRITICALCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
3.1CNACVSS9.9CRITICALCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Canonical LXD affected 5.0.0 5.0.8 semver Linux
CNA Canonical LXD affected 5.21.0 5.21.6 semver Linux

References

ReferenceSourceLinkTags
github.com/canonical/lxd/security/advisories/GHSA-v989-qw7w-xvg4 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Additional Advisory Data

Solutions

CNA: Upgrade to LXD version 5.0.8 or later, or 5.12.6 or later.

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