The WooCommerce Vindi Pagamento WordPress plugin through 0.8.3 does not perform any authorisation check when updating an order's shipment tracking code, and does not escape that code when displaying it on the order edit page, allowing unauthenticated attackers to perform Stored Cross-Site Scripting attacks against administrators and shop managers who view an order paid through the gateway. The stored payload is only rendered on sites using WooCommerce's legacy (WordPress posts) order storage.