The WordPress plugin, Email Subscribers & Newsletters, before 4.2.3 had a privilege bypass flaw that allowed authenticated users (Subscriber or greater access)…

The WordPress plugin, Email Subscribers & Newsletters, before 4.2.3 had a privilege bypass flaw that allowed authenticated users (Subscriber or greater access) to send test emails from the administrative dashboard on behalf of an administrator. This occurs because the plugin registers a wp_ajax function to send_test_email.