Oxygen Builder <= 4.8.3 - Missing Authorization to Authenticated (Subscriber+) Stylesheet Update

The Oxygen Builder plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the oxy_save_css_from_admin AJAX action in all versions up to, and including, 4.8.3. This makes it possible for authenticated attackers, with Subscriber-level access and above, to update stylesheets.