Canonical LXD up to 5.0.6/5.21.4/6.7.x Backup Import backup/index.yaml input validation

Summaryinfo

A vulnerability classified as critical was found in Canonical LXD up to 5.0.6/5.21.4/6.7.x. Affected by this vulnerability is an unknown functionality of the file backup/index.yaml of the component Backup Import. Such manipulation leads to input validation. This vulnerability is referenced as CVE-2026-34178. It is possible to launch the attack remotely. No exploit is available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Canonical LXD up to 5.0.6/5.21.4/6.7.x. Affected by this issue is an unknown function of the file backup/index.yaml of the component Backup Import. The manipulation with an unknown input leads to a input validation vulnerability. Using CWE to declare the problem leads to CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. Impacted is confidentiality, integrity, and availability. CVE summarizes:

In Canonical LXD before 6.8, the backup import path validates project restrictions against backup/index.yaml in the supplied tar archive but creates the instance from backup/container/backup.yaml, a separate file in the same archive that is never checked against project restrictions. An authenticated remote attacker with instance-creation permission in a restricted project can craft a backup archive where backup.yaml carries restricted settings such as security.privileged=true or raw.lxc directives, bypassing all project restriction enforcement and allowing full host compromise.

The weakness was published by Miha Purg. The advisory is available at github.com. This vulnerability is handled as CVE-2026-34178 since 03/26/2026. The exploitation is known to be easy. The attack may be launched remotely. The exploitation requires an enhanced level of successful authentication. Technical details are known, but there is no available exploit.

Upgrading to version 5.0.7, 5.21.5 or 6.8.0 eliminates this vulnerability.

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Productinfo

Vendor

• Canonical

Name

• LXD

Version

• 5.0.0
• 5.0.1
• 5.0.2
• 5.0.3
• 5.0.4
• 5.0.5
• 5.0.6
• 5.21.0
• 5.21.1
• 5.21.2
• 5.21.3
• 5.21.4
• 6.0
• 6.1
• 6.2
• 6.3
• 6.4
• 6.5
• 6.6
• 6.7

License

• open-source

Website

• Product: https://github.com/canonical/lxd/

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