Vulnerability Intelligence Report
Instance template path traversal allows arbitrary host file write as root
CVE-2026-66897
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.
Path Traversal
No Active Exploit Signals
CVSS Base Score
9.9
CRITICAL
Exploitability:3.2
Impact Score:6.1
EPSS Probability:0.62%
Executive Threat Verdict
Evaluating...
Evaluating Threat Landscape...
Assessing known weaponization, exploitation telemetry, and federal advisories.
Attack Surface
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Authentication
—
Weaponization
—
SSVC Action
—
Weaknesses (CWE)
Affected Products & Versions
| Vendor | Product | Affected Versions |
|---|---|---|
| Canonical | LXD | 4.0.0 < 4.0.13 (affected), 5.0.0 < 5.0.9 (affected), 5.21.0 < 5.21.7 (affected), 6.0 < 6.10 (affected) |
Threat Intelligence Signals
EPSS Score
0.619%
Vulnerability Class
Path Traversal
Identity & Timeline
| Status | PUBLISHED |
| Assigning Authority | Canonical Ltd. · Vendor · UK |
| Reserved | 2026-07-28T07:41:26 |
| Published | 2026-08-24T09:08:04 |
| Last Updated | 2026-08-25T03:55:49 |
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