The Paystack WooCommerce Payment Gateway plugin for WordPress is vulnerable to Sensitive Information Exposure in all versions up to, and including, 5.8.5 via the 'key' parameter. This makes it possible for unauthenticated attackers to extract customer PII — including billing name, email address, phone number, billing address, shipping address, and purchased product list — embedded into page HTML via wp_localize_script by enumerating sequential order IDs. This is only exploitable when the merchant has enabled the optional custom metadata feature in the Paystack gateway settings.