CVE-2026-66897
Instance template path traversal allows arbitrary host file write as root
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.
INFO
Published Date :
Aug. 24, 2026, 10:16 a.m.
Last Modified :
Aug. 24, 2026, 10:16 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | CRITICAL | cc1ad9ee-3454-478d-9317-d3e869d708bc | ||||
| CVSS 3.1 | CRITICAL | [email protected] |
Solution
- Update LXD to the latest version.
- Review and validate all image metadata.
- Restrict container edit permissions.
- Avoid launching untrusted images.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-66897.
| URL | Resource |
|---|---|
| https://github.com/canonical/lxd/security/advisories/GHSA-q39m-8fx9-42fv |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-66897 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-66897
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-66897 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-66897 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Aug. 24, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://github.com/canonical/lxd', 'vendor': 'Canonical', 'product': 'LXD', 'versions': [{'status': 'affected', 'version': '4.0.0', 'lessThan': '4.0.13', 'versionType': 'semver'}, {'status': 'affected', 'version': '5.0.0', 'lessThan': '5.0.9', 'versionType': 'semver'}, {'status': 'affected', 'version': '5.21.0', 'lessThan': '5.21.7', 'versionType': 'semver'}, {'status': 'affected', 'version': '6.0', 'lessThan': '6.10', 'versionType': 'semver'}], 'platforms': ['Linux'], 'packageName': 'LXD', 'defaultStatus': 'unaffected'}] 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. Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H Added CWE CWE-22 Added CWE CWE-23 Added Reference https://github.com/canonical/lxd/security/advisories/GHSA-q39m-8fx9-42fv