Hw64.sys in Marvin Test HW.exe prior to 5.0.5.0 allows unprivileged user-mode processes to arbitrarily map physical memory via IOCTL 0x9c406490 (for IoAllocateMdl, MmBuildMdlForNonPagedPool, and MmMapLockedPages), leading to NT AUTHORITY\SYSTEM privilege escalation.
Vulmon