Hw64.sys in Marvin Test HW.exe before 5.0.5.0 allows unprivileged user-mode processes to arbitrarily map physical memory with read/write access via the MmMapIoSpace API (IOCTL 0x9c40a4f8, 0x9c40a4e8, 0x9c40a4c0, 0x9c40a4c4, 0x9c40a4ec, and seven others), leading to a denial of service (BSOD).
https://www.marvintest.com/KnowledgeBase/KBArticle.aspx?ID=362
https://www.marvintest.com/Downloads.aspx?prodId=12&search=package