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Fencer Intel
critical 9.9

CVE-2026-85526 json

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

published last mo. modified last mo. also EUVD-2026-88257 , GHSA-h85r-gjgx-g2rv

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
9.9
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 45%
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

Is CVE-2026-85526 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

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

Exploit prediction

0.53% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-11).

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 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.