Microsoft Exchange Server 2007 SP2 on the x64 platform allows remote authenticated users to cause a denial of service (infinite loop and MSExchangeIS outage) via a crafted RPC request, aka "Exchange Server Infinite Loop Vulnerability."
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A12019
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2010/ms10-106
http://www.us-cert.gov/cas/techalerts/TA10-348A.html