What’s Vulnerable › Vulnerabilities
CVE-2026-85185: Path traversal in LXD btrfs storage driver allows arbitrary file deletion and write on host as root
- Severity: critical (CVSS 9.6 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.4% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-09-28 · updated 2026-09-28
- Weakness: CWE-22
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.
Affected products
- Canonical LXD: from 4.0.2 before 4.0.14; from 5.0.0 before 5.0.10; from 5.21.0 before 5.21.8; from 6.0 before 6.10 — fixed in 4.0.14, 5.0.10, 5.21.8, 6.10
How to fix
Upgrade to a fixed version: Canonical LXD 4.0.14, 5.0.10, 5.21.8, 6.10. Check the vendor advisory for mitigations.
References
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