WP Hotel Booking <= 2.1.9 is vulnerable to Cross Site Request Forgery (CSRF) Vulnerability

The WP Hotel Booking plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions up to, and including, 2.1.9. This is due to missing or incorrect nonce validation on the save() function. This makes it possible for unauthenticated attackers to update plugin settings via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.