Description
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.
Published: 2026-09-28
Score: 9.6 Critical
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

Vendor Solution

Upgrade to LXD versions 4.0.14, 5.0.10, 5.21.8, 6.10 or later.

Tracking

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Advisories

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History

Mon, 28 Sep 2026 17:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Mon, 28 Sep 2026 15:15:00 +0000

Type Values Removed Values Added
First Time appeared Canonical
Canonical lxd
Vendors & Products Canonical
Canonical lxd

Mon, 28 Sep 2026 13:30:00 +0000

Type Values Removed Values Added
Description 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.
Title Path traversal in LXD btrfs storage driver allows arbitrary file deletion and write on host as root
Weaknesses CWE-22
References
Metrics cvssV3_1

{'score': 9.6, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: canonical

Published:

Updated: 2026-09-28T16:32:28.529Z

Reserved: 2026-09-03T11:46:34.569Z

Link: CVE-2026-85185

cve-icon Vulnrichment

Updated: 2026-09-28T16:22:32.628Z

cve-icon NVD

Status : Deferred

Published: 2026-09-28T14:17:20.130

Modified: 2026-09-28T17:17:51.013

Link: CVE-2026-85185

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-28T15:30:02Z

Weaknesses
  • CWE-22

    Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')