Path Traversal in Canonical Lxd
CVE-2026-85185
Path traversal in the btrfs storage driver in Canonical LXD versions 4.0.2 and later (fixed in 4.0.14, 5.0.10, 5.21.8 and 6.10) on Linux allows an authenticated client with permission to create instances in a project to delete arbitrary files on the host as root. On hosts whose root filesystem is btrfs, the client can also place attacker-controlled content at arbitrary host paths, leading to full host compromise. The client does this with a crafted subvolume path containing ../ sequences, sent in either of two ways: in the optimized_header.yaml of an optimized btrfs backup, or in the btrfs migration header sent by a malicious migration source.
Vulnerability class: Path Traversal (Directory Traversal)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.6 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/canonical/lxd/security/advisories/GHSA-27q7-qwhm-c34p (vendor-advisory)
Frequently asked questions
- What is CVE-2026-85185?
- CVE-2026-85185 is a critical-severity vulnerability in Canonical Lxd, classified under Path Traversal. CVSS score: 9.6/10. Published 2026-09-28.
- How severe is CVE-2026-85185?
- Critical severity. CVSS v3 base score is 9.6 out of 10.