Print Invoice & Delivery Notes for WooCommerce <= 5.4.1 - Unauthenticated Sensitive Information Exposure Through Unprotected Directory

The Print Invoice & Delivery Notes for WooCommerce plugin for WordPress is vulnerable to Sensitive Information Exposure in all versions up to, and including, 5.4.1 via the 'wcdn/invoice' directory. This makes it possible for unauthenticated attackers to extract sensitive data stored insecurely in the /wp-content/uploads/wcdn/invoice directory which can contain invoice files if an email attachment setting is enabled.