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Fencer Intel
critical 9.9

CVE-2026-63297 json

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

published 3mo ago modified 18d ago also EUVD-2026-57513 , GHSA-v989-qw7w-xvg4

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository canonical/lxd. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
9.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 28%
public exploits
0
none known

Summary

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.

Patch / fix

  • Canonical LXD 5.0.8, 5.21.6
  • lxd openSUSE Leap 16.0 5.21.6-bp160.1.1

opensuse advisories openSUSE-SU-2026:21788-1

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
2mo ago

Exploit prediction

0.34% chance of exploitation in the next 30 days, higher than 28% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • github.com https://github.com/canonical/lxd/security/advisories/GHSA-v989-qw7w-xvg4 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 9.9 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected products

  • Canonical LXD

Classification

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

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of canonical/lxd published their own advisory on GitHub. Reviewed sources take precedence over it.