Multiple vulnerabilities have been discovered in Microsoft Exchange Server that could allow remote code execution. Two of the vulnerabilities exist in the WebReady Document Viewing feature. Two other vulnerabilities are caused by the Exchange Server not properly validating input. Exploitation of these vulnerabilities could be caused by an attacker sending specially crafted content to the Exchange Server or as an email attachment.  Successful exploitation could result in the attacker gaining the same user rights as the LocalService account or the logged on user. Depending on the privileges associated with the account, an attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.