CVE-2026-71259
ESPHome external_components file:// Scheme Validation Bypass Leading to Remote Code Execution
ESPHome through 2026.7.0-dev contains an operator-precedence bug in the cv.url() validator in esphome/config_validation.py: `if parsed.scheme and parsed.netloc or parsed.scheme == "file": return parsed.geturl()`. Because `and` binds tighter than `or`, any file: URI passes validation regardless of netloc. This validator gates the `url:` field of the external_components YAML directive's git source schema, which is passed to `git clone` (git supports file:// natively). A crafted `external_components` block with `url: "file:///attacker/repo"` clones an attacker-controlled local path, which is then added to Python's import machinery via ESPHome's component loader, executing arbitrary Python code when the YAML configuration is processed (e.g. via `esphome config`/`esphome run`).
| CWE | CWE-184 |
| Vendor | esphome |
| Product | esphome |
| Published | Aug 5, 2026 |
| Last Updated | Aug 5, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H