It was just released by cPanel that there is a major security hole in some versions of Horde webmail. We are going through and updating all our servers immediately to ensure that this hole is plugged. If you are on our shared servers there is nothing that you need to do, we have it under control.

 If you are running a dedicated server with horde on it, please update it immediately. If your not sure how to do that please open a ticket with support and they can help you with upgrading.