A vulnerability in the AMD uProf kernel driver (AmdTools64.sys) version 5.3.521.0 allows local users with a handle to the driver to read and write Model-Specific Registers (MSRs) without proper validation. This enables an elevation of privilege (EoP) by overwriting the IA32_LSTAR MSR, which controls the CPU's syscall entry point, allowing execution of arbitrary code at kernel privilege level (CPL0). The exploit bypasses Kernel Address Space Layout Randomization (KASLR) and SMEP protections to escalate privileges to SYSTEM on Windows 10 x64 22H2. On Windows 11 with Memory Integrity enabled, the write is blocked. The vulnerability requires administrative rights to load the driver but then allows ring-0 code execution. AMD was notified but did not acknowledge the issue as of the report date.