This could allow a malicious actor to delete files from your website. If core files are deleted from your website, it could cause your site to break and stop functioning.
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 1.9.5 or later to remove the vulnerability. Patchstack users can turn on auto-update for vulnerable plugins only.