Path traversal via Btrfs optimized-backup subvolumes[].path enables root file/dir manipulation in LXD

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-85526
StatePUBLISHED
Assignercanonical
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-28 14:17:20 UTC
Updated2026-09-29 04:18:00 UTC
DescriptionPath 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.

Risk And Classification

Primary CVSS: v3.1 9.9 CRITICAL from [email protected]

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

EPSS: 0.005160000 probability, percentile 0.416350000 (date 2026-09-29)

Problem Types: CWE-22 | CWE-22 CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary9.9CRITICALCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
3.1CNACVSS9.9CRITICALCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Canonical LXD affected 4.0.0 4.0.14 semver Linux
CNA Canonical LXD affected 5.0.0 5.0.10 semver Linux
CNA Canonical LXD affected 5.21.0 5.21.8 semver Linux
CNA Canonical LXD affected 6.0 6.10 semver Linux

References

ReferenceSourceLinkTags
github.com/canonical/lxd-private/pull/104 [email protected] github.com
github.com/canonical/lxd-private/pull/87 [email protected] github.com
github.com/canonical/lxd-private/pull/105 [email protected] github.com
github.com/canonical/lxd/security/advisories/GHSA-h85r-gjgx-g2rv [email protected] github.com
github.com/canonical/lxd-private/pull/84 [email protected] github.com
github.com/canonical/lxd-private/pull/103 [email protected] github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Additional Advisory Data

Solutions

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

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