Patreon WordPress < 1.7.2 - Reflected XSS on Login Form

The Jetpack Scan team identified a Reflected Cross-Site Scripting in the Login Form of the Patreon WordPress plugin before 1.7.2. The WordPress login form (wp-login.php) is hooked by the plugin and offers to allow users to authenticate on the site using their Patreon account. Unfortunately, some of the error logging logic behind the scene allowed user-controlled input to be reflected on the login page, unsanitized.