The Seo Monster plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 3.3.3. This is due to missing or incorrect nonce validation on the check_integration() function. This makes it possible for unauthenticated attackers to update settings and inject malicious web scripts via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.
https://plugins.trac.wordpress.org/browser/seo-monster/trunk/tpl/integration.php#L42
https://plugins.trac.wordpress.org/browser/seo-monster/trunk/inc/class_seo_monster_ui.php#L69