If you run DNS on Microsoft Windows, pay careful attention to the MS-15-127 patch.
Microsoft rates this patch as critical for most Windows platforms running DNS services.
Remote exploits are possible, including remote code execution. Attackers exploiting this issue could obtain Local System context and privileges.
We are currently aware that reverse engineering of the patch has begun by researchers and exploit development is under way in the underground pertaining to this issue. A working exploit is likely to be made available soon, if it is not already in play, as you read this.