This could allow a malicious actor to determine if something does or does not exist in a database or filesystem. 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 2.8.1 or later to resolve the vulnerability.