The Wired Impact Volunteer Management WordPress plugin before 2.8.2 does not have authorisation checks in one of its AJAX actions, and does not verify that the RSVP being removed belongs to the requesting user, allowing users with a role as low as Subscriber to remove arbitrary users' RSVPs from any volunteer opportunity.
https://wpscan.com/vulnerability/7541bc1a-a4ea-4e02-b10a-ea59708159f4/