The server in Kerberos in Microsoft Windows Server 2008 R2 and R2 SP1, and Windows 7 Gold and SP1, allows remote attackers to cause a denial of service (NULL pointer dereference and reboot) via a crafted session request, aka "Kerberos NULL Dereference Vulnerability."
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A15674
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2012/ms12-069
http://www.us-cert.gov/cas/techalerts/TA12-283A.html
http://www.securitytracker.com/id?1027620