Microsoft plans to fix a buffer overflow in its Vector Markup Language (VML) dll on October 10th. In the meantime your IE browser and some email readers are vunerable to attack. To fix the problem run this command on your machine and reboot:
regsvr32 -u "%ProgramFiles%\Common Files\Microsoft Shared\VGX\vgx.dll"
This unregisters the VML renderer, which is sparsely used today. To reregister the dll after October 10th,
regsvr32 "%ProgramFiles%\Common Files\Microsoft Shared\VGX\vgx.dll"
Don't take my word for it though, read Microsoft's note here.