DescriptionPassMark PerformanceTest before 11.1 build 1012, BurnInTest before 11.1 build 1000, and OSForensics before 11.1 build 1016 contain a privilege escalation and denial-of-service vulnerability in DirectIo64.sys that allows local attackers to read arbitrary Model-Specific Registers or write zero to any MSR through exposed IOCTLs with insufficient blocklist enforcement. Attackers can exploit the unrestricted write IOCTL to zero out the system call handler MSR, causing an immediate unrecoverable kernel crash on the next system call, or read security-sensitive MSRs used to locate kernel data structures.