The Microsoft Antimalware Client in Windows Defender on Windows 8 and Windows RT uses an incorrect pathname for MsMpEng.exe, which allows local users to gain privileges via a crafted application, aka "Microsoft Antimalware Improper Pathname Vulnerability."
Improper Input Validation The product receives input or data, but it does
not validate or incorrectly validates that the input has the
properties that are required to process the data safely and
correctly.