This patch Tuesday Microsoft released MS12-025 that fixes approximately a zillion vulnerabilities in System.Drawing.dll.

Here's what they fixed (multiple instances of each issue):

• Added security demands to unsafe methods.
• Wrap handles in SafeHandle instead of using IntPtr.
• Use checked to guard against integer overflow when calculating how many bytes to AllocHGlobal.

It's a little embarassing to have so many vulnerabilities in this old code. Luckily, silently running .NET code in the browser is becoming a thing of the past.