CVE-2026-63300: canonical lxd

CVSS 9.9 (critical) · published 2026-08-12

An improper validation vulnerability in the instancePostMigration function in lxd/instance_post.go of LXD allows an authenticated attacker with can_create_instances permissions on a restricted project to bypass project-level security restrictions. When migrating an instance between projects, LXD fails to validate the instance's configuration against the target project's enforced restrictions (such as restricted.containers.lowlevel, restricted.devices.*, and restricted.networks.access). An attacker can exploit this by creating a disallowed or high-privilege instance in an unrestricted project and subsequently moving it into the restricted project.

Affected products (NVD): canonical lxd

Fixed in (NVD): 5.0.8, 5.21.6, 6.10

Weakness: CWE-862

Source: NVD CVE-2026-63300

References

• https://github.com/canonical/lxd/pull/18605
• https://github.com/canonical/lxd/pull/18651
• https://github.com/canonical/lxd/security/advisories/GHSA-5g5r-wh97-qcq2

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