Funnelforms Free <= 3.4 - Cross-Site Request Forgery to Arbitrary Post Deletion

The Funnelforms Free plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions up to, and including, 3.4. This is due to missing or incorrect nonce validation on the fnsf_delete_posts function. This makes it possible for unauthenticated attackers to delete arbitrary posts via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.