The Spin Wheel plugin for WordPress is vulnerable to client-side prize manipulation in all versions up to, and including, 2.1.0. This is due to the plugin trusting client-supplied prize selection data without server-side validation or randomization. This makes it possible for unauthenticated attackers to manipulate which prize they win by modifying the 'prize_index' parameter sent to the server, allowing them to always select the most valuable prizes.
