pCloud WP Backup < 2.0.4 - Missing Authorization on the 'start_backup' AJAX Method to Authenticated (Subscriber+) Arbitrary File Read

Description

The pCloud WP Backup plugin for WordPress is vulnerable to Sensitive Information Exposure in all versions up to, and including, 2.0.3 via the wp2pcl_ajax_process_request_inner. This makes it possible for authenticated attackers, with subscriber-level access and above, to extract force generation of a full-site backup archive written to a publicly accessible directory, exposing wp-config.php database credentials, WordPress secret salts, and the complete PHP source tree. The resulting archive is deposited in the plugin's unprotected tmp/ directory at a predictable URL, making the extracted data accessible to unauthenticated visitors once the backup is triggered.