CVE-2026-85526 Path traversal via Btrfs optimized-backup subvolumes[].path enables root file/dir manipulation in LXD

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/optimizedheader.yaml...