Happy Addons for Elementor <= 3.8.2 - Cross-Site Request Forgery via handle_optin_optout()

The Happy Addons for Elementor plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions up to, and including, 3.8.2. This is due to missing nonce validation on the handle_optin_optout() function. This makes it possible for unauthenticated attackers to modify optin and optout settings, via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.