Double free vulnerability in Microsoft Silverlight 4 before 4.1.10329 on Windows allows remote attackers to execute arbitrary code via vectors involving crafted XAML glyphs, aka "Silverlight Double-Free Vulnerability."
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A15574
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2012/ms12-034
http://www.us-cert.gov/cas/techalerts/TA12-129A.html
http://www.securitytracker.com/id?1027040