Simple Calendar < 3.2.5 - Cross-Site Request Forgery via duplicate_feed

Description

The Simple Calendar – Google Calendar Plugin plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to 3.2.5 (exclusive). This is due to missing or incorrect nonce validation on the duplicate_feed function. This makes it possible for unauthenticated attackers to duplicate feeds via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.