Instant CSS <= 1.2.1 - Cross-Site Request Forgery

The Instant CSS plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions up to, and including, 1.2.1. This is due to missing or incorrect nonce validation on several functions called via AJAX actions in the class.instantcss_ajax.php file. This makes it possible for unauthenticated attackers to save and retrieve theme data, css data, minify data, and preprocessor data via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.