CVE-2026-85185
Path traversal in LXD btrfs storage driver allows arbitrary file deletion and write on host as root
- Published
- Updated
- Reserved
- Assigned by
- canonical
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.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. CISA's SSVC rates its exploitation: a proof of concept is public.
Timeline
ID reserved
By canonical
- 25 days later
· 25 days later
Published
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| canonicalCNA (assigner) | 3.1 | Critical9.6 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H |
| NVDNVD · Deferred | 3.1 | Critical9.6 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.37% · top 69% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.6.
Weakness
Affected products
What to do
Solution: Upgrade to LXD versions 4.0.14, 5.0.10, 5.21.8, 6.10 or later.
References (1)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-85185)Record last updated .