The Slek Gateway for WooCommerce plugin for WordPress is vulnerable to Information Exposure in version 1.0. This is due to the wsb_handle_slek_payment_redirect() function placing the merchant's slek_key and slek_secret API credentials directly into a client-side HTML form, and additionally embedding the slek_secret as a plaintext GET parameter in the IPN callback URL. This makes it possible for unauthenticated attackers who can place an order on the affected store to extract the merchant's API credentials by viewing the HTML source or using browser DevTools on the WooCommerce order-pay page before the JavaScript auto-submit fires.