Microsoft Forefront Threat Management Gateway (TMG) 2010 may leak some memory when you access a site that is listed in the HTTPS Inspection exception list. After a while, these leaks may cause performance issues for the Forefront TMG firewall service.
This issue occurs because Forefront TMG 2010 does not correctly free a certificate context.
2433623 Software Update 2 for Microsoft Forefront Threat Management Gateway (TMG) 2010 Service Pack 1
To work around this issue, remove the sites from the HTTPS Inspection exception list. Or, schedule regular restarts of the Forefront TMG firewall service when the used memory increases to a high proportion of the physical memory.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:
824684 Description of the standard terminology that is used to describe Microsoft software updates