Highcompress Image Compressor <= 5.0.0 - Missing Authorization via multiple AJAX actions

The Highcompress Image Compressor plugin for WordPress is vulnerable to unauthorized modification of datadue to a missing capability check on the 'verify_highcompress_process_auto', 'verify_highcompress_process_images', and 'verify_highcompress_api_key' AJAX functions in versions up to, and including, 5.0.0. This makes it possible for authenticated attackers, with subscriber-level access and above, to compress images and verify or modify the plugin's API key.