Podlove Subscribe button <= 1.3.7 - Cross-Site Request Forgery via save function

The Podlove Subscribe button plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions up to, and including, 1.3.7. This is due to missing or incorrect nonce validation on the save function. This makes it possible for unauthenticated attackers to make format updates via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.