All vulnerabilities
CVE-2026-85526GHSA-h85r-gjgx-g2rv

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

Canonical LXD
Open in ThreatlineRecord JSON
CVSS
9.9Critical
ExploitationPublic exploit codeCISA's assessment says proof of concept code is public, assessed 28 Sep 2026. Not in the KEV catalogCISA via CVE List
Exploit odds (EPSS)0.52%Chance of exploitation activity in the next 30 days, higher than 43% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in4.0.14Also 5.0.10, 5.21.8 and 1 moreCVE List
Published28 Sep 2026Updated 29 Sep 2026CVE List

What fixes it

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

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.

Text from CVE List

Affected versions 4

  • LXDaffected: 4.0.0 before 4.0.14CVE List
  • LXDaffected: 5.0.0 before 5.0.10CVE List
  • LXDaffected: 5.21.0 before 5.21.8CVE List
  • LXDaffected: 6.0 before 6.10CVE List

References 6