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CVE-2026-85526 Details

ANALYZED

This CVE record has been analyzed and enriched by NVDAPI.com as an independent party.

Description

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.

Metrics

CVSS 3.x Severity and Vector Strings:

VolerionCVSS-B:8.2 HIGHVector:CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N

CNA: [email protected]CVSS-B:9.9 CRITICALVector:CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

References to Advisories, Solutions, and Tools

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URL	Source(s)	Tag(s)
https://github.com/canonical/lxd-private/pull/103	[email protected]	Broken LinkIssue TrackingVendor
https://github.com/canonical/lxd-private/pull/104	[email protected]	Broken LinkVendor
https://github.com/canonical/lxd-private/pull/105	[email protected]	Broken LinkVendor
https://github.com/canonical/lxd-private/pull/84	[email protected]	Broken LinkIssue TrackingVendor
https://github.com/canonical/lxd-private/pull/87	[email protected]	Broken LinkIssue TrackingVendor
https://github.com/canonical/lxd/security/advisories/GHSA-h85r-gjgx-g2rv	[email protected]	AdvisoryExploitRemedyTechnical AnalysisVendor

see all 6 references

Weakness Enumeration

CWE-ID	CWE Name	Source
CWE-22	Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')	[email protected]

Affected Products

Product	Versions
Canonical LXD	>= 4.0.2 (semver)
CPE cpe:2.3:a:canonical:lxd:::::::: Remediation Upgrade: 4.0.14moderate effort Upgrade: 5.0.10moderate effort Upgrade: 5.21.8moderate effort Upgrade: 6.9-bf243damoderate effort Upgrade: 6.10moderate effort Mitigation:low effort Restrict the "can_create_instances" and "can_create_storage_volumes" permissions to trusted administrators. Mitigation:low effort Do not use the btrfs optimized-backup import path with untrusted tarballs. Mitigation:low effort Accept backups only from authenticated, integrity-verified sources. Mitigation:low effort Consider disallowing backup import for non-admin members in multi-tenant restricted projects until a fix is available.

Product

Versions

Canonical LXD

>= 4.0.2 (semver)

CPE

cpe:2.3:a:canonical:lxd:*:*:*:*:*:*:*:*

Remediation

Upgrade: 4.0.14moderate effort
Upgrade: 5.0.10moderate effort
Upgrade: 5.21.8moderate effort
Upgrade: 6.9-bf243damoderate effort
Upgrade: 6.10moderate effort
Mitigation:low effort
Restrict the "can_create_instances" and "can_create_storage_volumes" permissions to trusted administrators.
Mitigation:low effort
Do not use the btrfs optimized-backup import path with untrusted tarballs.
Mitigation:low effort
Accept backups only from authenticated, integrity-verified sources.
Mitigation:low effort
Consider disallowing backup import for non-admin members in multi-tenant restricted projects until a fix is available.

Change History

3 change records found show changes

Date	Action	Recorded By
Sep 29, 2026	CVE Modified	CISA-ADP
Sep 28, 2026	New CVE Received	[email protected]
Sep 28, 2026	CVE Modified	CISA-ADP