Path Traversal Vulnerability in Canonical LXD Btrfs Driver

CVE-2026-85526

What is CVE-2026-85526?

A vulnerability exists in the Btrfs storage driver used by Canonical LXD on Linux systems, which allows an authenticated user with the ability to create instances to exploit crafted entries in backup configurations. This vulnerability enables such users to delete or replace arbitrary files and directories on the host filesystem with root privileges. A crafted subvolumes[].path entry in the backup/optimized_header.yaml can lead to unauthorized modifications to the filesystem, posing significant risks to system integrity and security.

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