iPOSpays Gateways WC <= 1.3.7 - Unauthenticated Missing Authorization to Settings Update via REST API Endpoint

The iPOSpays Gateways WC plugin for WordPress is vulnerable to Missing Authorization in versions up to and including 1.3.7. This is due to the plugin exposing a REST API endpoint /wp-json/ipospays/v1/save_settings with 'permission_callback' set to '__return_true', which allows unauthenticated access without any capability checks or nonce verification. This makes it possible for unauthenticated attackers to update plugin settings, specifically allowing them to overwrite critical payment gateway settings including live API keys, secret keys, and payment tokens stored in the 'woocommerce_ipospays_settings' option.