This could allow a malicious actor to download any file from your website. This includes but is not limited to files that contain login credentials or backup files.
CVSS score is a way to evaluate and rank reported vulnerabilities in a standardized and repeatable way but which is not ideal for WordPress.
This security issue has a low severity impact and is unlikely to be exploited.
Update to version 1.1 or later to remove the vulnerability. Patchstack users can turn on auto-update for vulnerable plugins only.