The User Registration & Membership WordPress plugin before 5.2.3 does not perform a capability check for unauthenticated callers on one of its membership payment actions and acts on a caller-supplied user identifier, allowing unauthenticated attackers to delete recently-registered, payment-pending user accounts.
https://wpscan.com/vulnerability/8e3be064-b3b7-4d68-960b-8c850c3e6f77/