Microsoft .NET Framework 4 does not properly compare index values, which allows remote attackers to cause a denial of service (application hang) via crafted requests to a Windows Presentation Foundation (WPF) application, aka ".NET Framework Index Comparison Vulnerability."
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A15580
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2012/ms12-034