CVE-2026-66897

Critical

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.

SeverityCritical
CVSS9.9
Exploit probability—
ProductCanonical Lxd
PublishedAug 24, 2026
First seenAug 24, 2026

How to fix

Update
  • canonical lxd4.0.13, 5.0.9, 5.21.7 or later

Affected products

ProductAffected versionsFixed in
canonical lxdv < 4.0.13, 5.0.0 ≤ v < 5.0.9, 5.1 ≤ v < 5.21.7, 6.0 ≤ v ≤ 6.94.0.13, 5.0.9, 5.21.7

Check your version

Choose the product and enter the version you run to see whether it falls in the affected range.

In the Intelligence 360 plan

Attack Surface Management

See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.