CVE-2026-63297 Cross-project instance copy bypasses target project restrictions via TOCTOU in config merge

What is CVE-2026-63297?

CVE-2026-63297 is a critical vulnerability in Canonical LXD, published on 12 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official 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.

Weakness: CWE-863, CWE-367

Which versions are affected by CVE-2026-63297?

It affects 1 product.

Products include Canonical Lxd.

How do I fix CVE-2026-63297?

Apply the vendor's patch.

Is CVE-2026-63297 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-63297 exists.

Other vulnerabilities in Canonical LXD

• CVE-2026-66897 Instance template path traversal allows arbitrary host file write as root Critical 9.9
• CVE-2026-62420 Cross-project cluster migration bypasses project restrictions via cluster notification flag Critical 9.9
• CVE-2026-63293 Arbitrary File Read/Write: metadata.yaml symlink in image allows host filesystem access as root Critical 9.9
• CVE-2026-63294 Root RCE via image backup.yaml symlink Critical 9.9
• CVE-2026-63296 Project restriction bypass via instance migration config override Critical 9.9

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2026-63297, GHSA-v989-qw7w-xvg4, UBUNTU-CVE-2026-63297.