CVE-2026-86334: CLI Path Traversal via Content-Disposition in LXD Image Export/Copy
Path traversal in the CLI client image export and copy functionality in Canonical LXD from 4.0.2 before 4.0.14, 5.0.10, 5.21.8, and 6.10 on all platforms allows a remote malicious or machine-in-the-middle image server to overwrite arbitrary local files and execute code on the client system via a crafted Content-Disposition header filename parameter during unified image export or copy operations into a local directory target.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Canonical LXDto a version that resolves this vulnerability.Fixed in 4.0.14 - Upgrade
Upgrade
Canonical LXDto a version that resolves this vulnerability.Fixed in 5.0.10 - Upgrade
Upgrade
Canonical LXDto a version that resolves this vulnerability.Fixed in 5.21.8 - Upgrade
Upgrade
Canonical LXDto a version that resolves this vulnerability.Fixed in 6.10
Event History
Frequently Asked Questions
Which LXD client operations are exposed?
The affected CLI paths are unified image export and copy operations when their destination is a local directory. The issue is on the client system, regardless of platform.
What must an attacker control or intercept to exploit this?
The attacker must operate a malicious image server or be able to act as a machine-in-the-middle for the image server connection. They use a crafted Content-Disposition filename parameter while the user performs an affected export or copy operation.
Does exploitation require credentials or other local privileges?
No privileges are required by the attacker, but exploitation requires user interaction: a user must initiate the affected CLI image export or copy operation to a local directory. Successful exploitation can overwrite arbitrary local files and lead to code execution on that client system.
Which versions include fixes?
Fixed releases are 4.0.14, 5.0.10, 5.21.8, and 6.10. Versions from 4.0.2 before those respective fixed releases are affected.