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Fencer Vulns
critical 9.9

CVE-2026-85526 json

Path traversal via Btrfs optimized-backup subvolumes[].path enables root file/dir manipulation in LXD

published 2026-09-28 41 d ago modified 2026-09-29 41 d ago also EUVD-2026-88257

cvss
9.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 44%
public exploits
0
none known

Summary

Path traversal in the Btrfs storage driver (unpackVolume) in Canonical LXD on Linux allows an authenticated user with instance creation privileges to delete or replace arbitrary files and directories on the host filesystem as root via a crafted subvolumes[].path entry in backup/optimized_header.yaml during a btrfs optimized backup import.

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-2026-85526

  • incus openSUSE Tumbleweed 7.5.1-1.1

opensuse advisories openSUSE-SU-2026:11983-1

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
42 d ago

Exploit prediction

0.53% chance of exploitation in the next 30 days, higher than 44% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 9.9 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected products

  • Canonical LXD

Classification

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

References

Sources

Fencer Vulns 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.