Hw64.sys in Marvin Test HW.exe before 5.0.5.0 allows unprivileged user-mode processes to arbitrarily read kernel memory (and consequently gain all privileges) via IOCTL 0x9c4064b8 (via MmMapIoSpace) and IOCTL 0x9c406490 (via ZwMapViewOfSection).
The product reads data past the end, or before the beginning, of the intended buffer.