Vulnerability Intelligence Report
Path traversal via Btrfs optimized-backup subvolumes[].path enables root file/dir manipulation in LXD
CVE-2026-85526
Path traversal in the Btrfs storage driver (unpackVolume) in Canonical LXD on Linux allows an authenticated user with instance creation privileges to delete or replace arbitrary files and directories on the host filesystem as root via a crafted subvolumes[].path entry in backup/optimized_header.yaml during a btrfs optimized backup import.
Path Traversal
No Active Exploit Signals
CVSS Base Score
9.9
CRITICAL
Exploitability:3.2
Impact Score:6.1
Executive Threat Verdict
Evaluating...
Evaluating Threat Landscape...
Assessing known weaponization, exploitation telemetry, and federal advisories.
Attack Surface
—
Authentication
—
Weaponization
—
SSVC Action
—
Weaknesses (CWE)
CWE-22 ↗CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Affected Products & Versions
| Vendor | Product | Affected Versions |
|---|---|---|
| Canonical | LXD | 4.0.0 < 4.0.14 (affected), 5.0.0 < 5.0.10 (affected), 5.21.0 < 5.21.8 (affected), 6.0 < 6.10 (affected) |
Threat Intelligence Signals
Vulnerability Class
Path Traversal
Identity & Timeline
| Status | PUBLISHED |
| Assigning Authority | Canonical Ltd. · Vendor · UK |
| Reserved | 2026-09-04T08:34:29 |
| Published | 2026-09-28T13:21:40 |
| Patch Date | 2026-09-25 |
| Last Updated | 2026-09-29T03:55:18 |
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