The SponsorMe plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via PHP_SELF Parameter in all versions up to, and including, 0.5.2 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link. The PHP_SELF value is reflected in two separate locations within the vulnerable function — a form action attribute and an anchor href attribute — both of which can be exploited by appending a crafted payload to the wp-admin/admin.php URL path.