Description
A path traversal vulnerability in LXD's instance template processing allows an attacker with container edit permissions, or any user launching a crafted image, to overwrite arbitrary files on the host system as root. When processing target template paths specified in metadata.yaml, LXD validates the path against a confined os.Root directory handle but subsequently opens and creates the file using os.Create with an unconfined string path. This discrepancy between path resolution checks and file creation allows an attacker to escape directory confinement, overwrite root-owned host files, and achieve host root code execution.
Published: 2026-08-24
Score: 9.9 Critical
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

Vendor Solution

Upgrade to LXD versions 4.0.13, 5.0.9, 5.21.7, 6.10 or later.

Tracking

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Advisories

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History

Mon, 24 Aug 2026 09:30:00 +0000

Type Values Removed Values Added
Description A path traversal vulnerability in LXD's instance template processing allows an attacker with container edit permissions, or any user launching a crafted image, to overwrite arbitrary files on the host system as root. When processing target template paths specified in metadata.yaml, LXD validates the path against a confined os.Root directory handle but subsequently opens and creates the file using os.Create with an unconfined string path. This discrepancy between path resolution checks and file creation allows an attacker to escape directory confinement, overwrite root-owned host files, and achieve host root code execution.
Title Instance template path traversal allows arbitrary host file write as root
Weaknesses CWE-22
CWE-23
References
Metrics cvssV3_1

{'score': 9.9, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H'}


Subscriptions

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cve-icon MITRE

Status: PUBLISHED

Assigner: canonical

Published:

Updated: 2026-08-24T09:08:04.188Z

Reserved: 2026-07-28T07:41:26.310Z

Link: CVE-2026-66897

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

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cve-icon OpenCVE Enrichment

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Weaknesses
  • CWE-22

    Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

  • CWE-23

    Relative Path Traversal