# CVE-2026-85185: incus: 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...

CVE-2026-85185 is fixed in incus on 1 platform, first by DEBIAN-CVE-2026-85185, released September 29, 2026. It is not reported as exploited. Patch Radar priority: Urgent.

- Web page: https://patchblox.com/security/cve/CVE-2026-85185
- Priority: Urgent
- CVSS: 9.6 (critical)
- EPSS: 0.0037
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 28, 2026

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | incus Debian 13.5 (trixie) | 6.0.4-2+deb13u1 | [DEBIAN-CVE-2026-85185](https://patchblox.com/security/data/fix/linux/debian-cve-2026-85185.md) | Sep 29, 2026 |
| Linux | incus Debian 14 | 7.0.1-5 | [DEBIAN-CVE-2026-85185](https://patchblox.com/security/data/fix/linux/debian-cve-2026-85185.md) | Sep 29, 2026 |

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Data as of 2026-11-08T13:06:02Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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