This host is missing an important security update according to Microsoft Bulletin MS13-026.
Successful exploitation will allow attackers to gain access to potentially sensitive information and that may aid in further attacks. Impact Level: Application
Apply the patch from below link, http://technet.microsoft.com/en-us/security/bulletin/ms13-026
The flaw is due to Microsoft Outlook for Mac loading certain tags when previewing an HTML email, which can be exploited to load content from a remote server and confirm the existence of the targeted email accounts.
Microsoft Office 2008 on Mac OS X Microsoft Office 2011 on Mac OS X