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Fencer Intel
critical 9.6

CVE-2026-85185 json

Path traversal in LXD btrfs storage driver allows arbitrary file deletion and write on host as root

published last mo. modified last mo. also EUVD-2026-88258 , GHSA-27q7-qwhm-c34p

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository canonical/lxd. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
9.6
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 31%
public exploits
0
none known

Summary

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.

Patch / fix

  • Canonical LXD 4.0.14, 5.0.10, 5.21.8, 6.10
  • incus Debian 13 6.0.4-2+deb13u1
  • incus Debian 14 7.0.1-5

debian advisories DEBIAN-CVE-2026-85185

  • incus openSUSE Tumbleweed 7.5.1-1.1

opensuse advisories openSUSE-SU-2026:11983-1

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
last mo.

Exploit prediction

0.37% chance of exploitation in the next 30 days, higher than 31% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 9.6 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:H

Affected products

  • Canonical LXD

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of canonical/lxd published their own advisory on GitHub. Reviewed sources take precedence over it.