PiWeb Disable payment method / Partial payment for WooCommerce before 1.1.10.9 contains a missing authorization vulnerability in the update_fees AJAX handler that allows unauthenticated attackers to modify and read other customers' orders. Attackers can reuse a nonce from their own order-pay page and supply sequential order_id values to change payment methods, recalculate fees, and disclose order line items and totals.