The Subscriptions for WooCommerce plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the wps_sfw_admin_cancel_susbcription() function in all versions up to, and including, 1.9.2. This is due to the function being hooked to the init action without any authentication or authorization checks, and only performing a non-empty check on the nonce parameter without actually validating it via wp_verify_nonce(). This makes it possible for unauthenticated attackers to cancel any active WooCommerce subscription by sending a crafted GET request with an arbitrary nonce value via the wps_subscription_id parameter.