The JIT compiler in Microsoft .NET Framework 4.0 on 64-bit platforms does not properly perform optimizations, which allows remote attackers to execute arbitrary code via a crafted .NET application that triggers memory corruption, aka ".NET Framework x64 JIT Compiler Vulnerability."
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A6824
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2010/ms10-077