[ CVE-2026-85185 · Published 28 Sep 2026 ]
Vulnerability in Canonical LXD
[ Why it matters ]Priority signals
- Public proof-of-concept exploit exists (CISA SSVC)
- Critical severity: CVSS 9.6
[ Description ]Official description
Path traversal in the btrfs storage driver in Canonical LXD versions 4.0.2 and later (fixed in 4.0.14, 5.0.10, 5.21.8 and 6.10) on Linux allows an authenticated client with permission to create instances in a project to delete arbitrary files on the host as root. On hosts whose root filesystem is btrfs, the client can also place attacker-controlled content at arbitrary host paths, leading to full host compromise. The client does this with a crafted subvolume path containing ../ sequences, sent in either of two ways: in the optimized_header.yaml of an optimized btrfs backup, or in the btrfs migration header sent by a malicious migration source.
[ Fixes ]Fixes and patches
No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.