Pearl <= 1.3.4 is vulnerable to Cross-Site Request Forgery (CSRF) vulnerability

The Pearl plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions up to, and including, 1.3.4. This is due to missing or incorrect nonce validation on the stm_save_hb_settings function. This makes it possible for unauthenticated attackers to create new or modify existing site headers via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.