Impact
This affects any LXD user in an environment where an unprivileged user may have root access to a container with an attached custom storage volume that has the security.shifted property set to true as well as access to the host as an unprivileged user.
The most common case for this would be systems using lxd-user with the less privileged lxd group to provide unprivileged users with an isolated restricted access to LXD. Such users may be able to create a custom storage volume with the necessary property (depending on kernel and filesystem support) and can then write a setuid binary from within the container which can be executed as an unprivileged user on the host to gain root privileges.
Patches
Patches for this issue are available:
The first commit changes the permissions for any new storage pool, the later commit adds a patch that applies it on startup to all existing storage pools.
These fixes are also available in the associated candidate snap channels for each LTS series:
We will be preparing intermediate releases to the associated stable snap channels shortly.
Workarounds
Permissions can be manually restricted until a patched version of LXD is deployed.
This is done with:
sudo nsenter --mount=/run/snapd/ns/lxd.mnt -- chmod 0700 /var/snap/lxd/common/lxd/storage-pools/*/{custom*,virtual-machines*,images}
sudo nsenter --mount=/run/snapd/ns/lxd.mnt -- chmod 0711 /var/snap/lxd/common/lxd/storage-pools/*/{containers*,buckets*}
Those are the same permissions which will be applied by the patched LXD for both new and existing storage pools.
References
This was reported to Incus publicly on Github here:
| Software | From | Fixed in |
|---|---|---|
github.com/canonical/lxd
|
- | 0.0.0-20251110144034-698854d0164f |
A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.
CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.
A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.
Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.
Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.
SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.