This vulnerability is highly dangerous and expected to become exploited.
This could allow a malicious actor to cause a website to execute website requests to an arbitrary domain of the attacker. This could allow a malicious actor to find sensitive information of other services running on 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.
We advise to mitigate or resolve the vulnerability immediately.
Patchstack has issued a mitigation rule to block any attacks until you have updated to a fixed version.
Update to version 2.6.32 or later to remove the vulnerability. Patchstack users can turn on auto-update for vulnerable plugins only.