CVE-2026-109991: FunnelKit Payment Gateway for Stripe WooCommerce <= 1.15.0.2 - Insecure Direct Object Reference to Unauthenticated Sensitive Information Exposure via 'order-pay' URL Path Parameter

The FunnelKit Payment Gateway for Stripe WooCommerce plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 1.15.0.2 via the 'order-pay (WP query var from /checkout/order-pay/<ID>/)' parameter due to missing validation on a user controlled key. This makes it possible for unauthenticated attackers to read the full billing PII — including name, email address, phone number, and complete street address — of any store order by enumerating sequential order IDs, as this data is emitted into the inline fkwcsdata JavaScript object via wplocalizescript on every matching page response. Exploitation occurs even when WooCommerce itself rejects the order-pay page request, because the plugin's wplocalizescript call runs independently of WooCommerce's own order-key validation on the same request.