The Advanced AJAX Page Loader plugin for WordPress is vulnerable to Cross-Site Request Forgery to Arbitrary File Upload in versions up to, and including, 2.7.7. This is due to missing nonce validation in the 'admin_init_AAPL' function and missing file type validation in the 'AAPL_options_validate' function. This makes it possible for unauthenticated attackers to upload arbitrary files on the affected site's server which may make remote code execution possible via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.