---
id: CVE-2026-85185
title: >-
  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 …
summary: >-
  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 …
severity: critical
cvss: 9.6
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H'
cwe:
  - CWE-22
vendor: Canonical
product: LXD
affected:
  - LXD >= 4.0.2 < 4.0.14
  - LXD >= 5.0.0 < 5.0.10
  - LXD >= 5.21.0 < 5.21.8
  - LXD >= 6.0 < 6.10
published: '2026-09-28'
updated: '2026-09-28'
sourceUpdated: '2026-09-28T15:12:32.657'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-85185'
references:
  - url: 'https://github.com/canonical/lxd/security/advisories/GHSA-27q7-qwhm-c34p'
    label: security@ubuntu.com
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-28T14:12:02.170Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.