Improper input validation in Canonical Lxd
CVE-2026-34178
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.
Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.007 (50.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 50th percentile — 50.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.007 · change: +0.003
Affected products
- Canonical Lxd — versions 4.12.0, 5.1.0, 6.0.0
Weakness classification (CWE)
References
- github.com/canonical/lxd/security/advisories/GHSA-q96j-3fmm-7fv4 (Exploit, vendor-advisory, Third Party Advisory, vdb-entry)
- github.com/canonical/lxd/pull/17921 (issue-tracking, patch, Issue Tracking)
Frequently asked questions
- What is CVE-2026-34178?
- CVE-2026-34178 is a critical-severity vulnerability in Canonical Lxd, classified under Improper Input Validation. CVSS score: 9.1/10. Published 2026-04-09.
- How severe is CVE-2026-34178?
- Critical severity. CVSS v3 base score is 9.1 out of 10.