The BirdSeed plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 2.2.0. This is due to missing nonce validation in the birdseed_plugin_settings_page() function. The function processes the 'birdseed_token' GET parameter and saves it to the database via update_option() without verifying a nonce. This makes it possible for unauthenticated attackers to change the plugin's BirdSeed token setting via a forged request, granted they can trick a site administrator into performing an action such as clicking a link.