The Premium Packages – Sell Digital Products Securely plugin for WordPress is vulnerable to Stored Cross-Site Scripting via 'cart_items[][product_name]' Parameter in all versions up to, and including, 7.2.1 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The checkout REST route uses permission_callback set to __return_true and the invoice loader performs no order ownership check, meaning an unauthenticated attacker can both persist the payload and ensure it is renderable to any logged-in user who accesses the invoice.