by Kastro
Paper/Archive/CVE-2026-85526

CVE-2026-85526

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

EPSS 0.5%public exploitCVSS 9.9
critical.is priorityof 100
49
CVSS 9.9 (CNA)9.9 / 10 × 3029.7Not in CISA KEV+300.0EPSS percentile 44.7.447 × 208.9Exploit: SSVC poc+1010.0SSVC exploitation: poc+100.0
Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
LXD4.0.0 – < 4.0.144.0.14CNA
LXD5.0.0 – < 5.0.105.0.10CNA
LXD5.21.0 – < 5.21.85.21.8CNA
LXD6.0 – < 6.106.10CNA

Scores by source

canonical (CNA)9.9CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
CISA ADPSSVCExploitation: poc · Automatable: no · Technical impact: total

References

advisorygithub.com/canonical/lxd/security/advisories/GHSA-h85r-gjgx-g2rvpatchgithub.com/canonical/lxd-private/pull/87patchgithub.com/canonical/lxd-private/pull/105patchgithub.com/canonical/lxd-private/pull/104patchgithub.com/canonical/lxd-private/pull/103patchgithub.com/canonical/lxd-private/pull/84