The code-optimization feature in the reflection implementation in Microsoft .NET Framework 4 and 4.5 does not properly enforce object permissions, which allows remote attackers to execute arbitrary code via (1) a crafted XAML browser application (aka XBAP) or (2) a crafted .NET Framework application, aka "WPF Reflection Optimization Vulnerability."
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A15960
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2012/ms12-074
http://www.us-cert.gov/cas/techalerts/TA12-318A.html
http://www.securitytracker.com/id?1027753
http://www.securityfocus.com/bid/56464