CVE-2026-34178 CRITICAL

CVE-2026-34178: Importing a crafted backup leads to project restriction bypass

Vendor Canonical
Product lxd
Weakness CWE-20 · Input validation
Published April 9, 2026
Last update April 9, 2026

CVSS base score

9.1/10
Attack vector Network
Attack complexity Low
Privileges required High
User interaction None
Confidentiality High
Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

April 9, 2026 CVE published
April 9, 2026 Record updated