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CVE PROGRAM SOURCE RECORD9.9 Critical

CVE-2026-66897

Instance template path traversal allows arbitrary host file write as root

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Status
Published
Published
Updated
Assigning organization
canonical

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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Canonical LXD

Default version status: unaffected

  • 4.0.0 to < 4.0.13affected
  • 5.0.0 to < 5.0.9affected
  • 5.21.0 to < 5.21.7affected
  • 6.0 to < 6.10affected

References