The WP Meta Sort Posts plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 0.9. This is due to missing or incorrect nonce validation on the top-level included script in msp-options.php. This makes it possible for unauthenticated attackers to change the plugin's msp_loop_file and msp_nav_location settings via a forged request via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.