The WPFunnels plugin for WordPress is vulnerable to a security issue known as Reflected Cross-Site Scripting. This issue affects versions up to and including 2.7.16. If an attacker is able to get a user to click on a malicious link, it could allow them to inject harmful web scripts into pages that are viewed by the user. This security issue is caused by a lack of proper sanitization and output escaping of the order_id parameter.