This could allow a malicious actor to see all files in a given directory or determine if certain files/directories exist in given folder. This can be used to exploit other weaknesses in the system
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 4.0.28 or later to remove the vulnerability. Patchstack users can turn on auto-update for vulnerable plugins only.