CVE-2026-63300 Cross-project instance move bypasses all project restrictions allowing host command execution
Authenticated attackers can bypass project restrictions by moving instances, enabling host command execution in restricted LXD environments.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-63300?
CVE-2026-63300 is a critical missing authorization 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 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.
Weakness: CWE-862
Which versions are affected by CVE-2026-63300?
It affects 1 product.
Products include Canonical Lxd.
How do I fix CVE-2026-63300?
No fix has been published for CVE-2026-63300 yet. Limit exposure of the affected software until one is available.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-63300 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-63300 exists.
Other vulnerabilities in Canonical LXD
- CVE-2026-66897 Instance template path traversal allows arbitrary host file write as root
- CVE-2026-62420 Cross-project cluster migration bypasses project restrictions via cluster notification flag
- CVE-2026-63293 Arbitrary File Read/Write: metadata.yaml symlink in image allows host filesystem access as root
- CVE-2026-63294 Root RCE via image backup.yaml symlink
- CVE-2026-63296 Project restriction bypass via instance migration config override
Sources
Also known as DEBIAN-CVE-2026-63300, GHSA-5g5r-wh97-qcq2, UBUNTU-CVE-2026-63300.