CVE-2026-85526Public exploitNetwork attack vectorHinoki check available

Root host-file manipulation via Btrfs backup traversal

Published Sep 28, 2026 · Updated Sep 28, 2026

Path traversal in Canonical LXD's Btrfs backup import allows remote authenticated users to delete or replace host files as root. The unpackVolume routine joins an unvalidated subvolumes[].path from backup/optimized_header.yaml to the volume mount path, then removes or renames the resulting host path. Exploitation requires instance-creation privileges, a Btrfs storage pool, and import of a crafted optimized backup; the resulting root-level file operations can disrupt or compromise the host.

CVSS severity9.9
Critical
EPSS probability0.52%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Path traversal in Canonical LXD's Btrfs backup import allows remote authenticated users to delete or replace host files as root. The unpackVolume routine joins an unvalidated subvolumes[].path from backup/optimized_header.yaml to the volume mount path, then removes or renames the resulting host path. Exploitation requires instance-creation privileges, a Btrfs storage pool, and import of a crafted optimized backup; the resulting root-level file operations can disrupt or compromise the host.

The record

CVE
CVE-2026-85526
Published
Sep 28, 2026
Updated
Sep 28, 2026
Vendor
Canonical Ltd.
Product
LXD
Classifications
CWE-22, T1565.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 28, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 28, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.0.0 <4.0.14
  2. Affected versionversion=5.0.0 <5.0.10
  3. Affected versionversion=5.21.0 <5.21.8
  4. Affected versionversion=6.0 <6.10

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Canonical Ltd. · LXDversion=4.0.0 <4.0.14; version=5.0.0 <5.0.10; version=5.21.0 <5.21.8; version=6.0 <6.10

Published CVSS scores

9.9Canonical LXD GitHub Security AdvisoryCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1565.001Stored Data Manipulation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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