CVE-2026-66897
criticalpriority · track · 0EPSS 0.007 · 54 %ileUSEPSS · scored 2026-10-27
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.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (4)
Products and version ranges known to be affected.
sources
Which sources assert this record, and when.
references (1) nvd
External citations — patches, advisories, analysis.
- https://github.com/canonical/lxd/security/advisories/GHSA-q39m-8fx9-42fvVendor AdvisoryExploit
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