The TNC Toolbox: Web Performance plugin for WordPress is vulnerable to Sensitive Information Exposure in all versions up to, and including, 1.4.2. This is due to the plugin storing cPanel API credentials (hostname, username, and API key) in files within the web-accessible wp-content directory without adequate protection in the "Tnc_Wp_Toolbox_Settings::save_settings" function. This makes it possible for unauthenticated attackers to retrieve these credentials and use them to interact with the cPanel API, which can lead to arbitrary file uploads, remote code execution, and full compromise of the hosting environment.