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."
Improper Control of Generation of Code The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.