Microsoft .NET Framework 4 does not properly allocate buffers, 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 ".NET Framework Buffer Allocation Vulnerability."
Improper Restriction of Operations within the Bounds of a Memory Buffer The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary.