Japanese researcher Kento Oki has discovered a bug in PatchGuard that could be exploited by an attacker to load unsigned malicious code into the Windows operating system kernel. PatchGuard, also known as Kernel Patch Protection, is a software protection utility that has been designed to forbid the kernel of 64-bit versions of Windows OS from being patched in order to prevent rootkit infections or the execution of malicious code at the kernel level. The vulnerability has yet to be addressed by Microsoft, which has previously ignored three other PatchGuard bypasses discovered in the past years.”]
Source: https://securityaffairs.co/wordpress/118427/hacking/microsoft-patchguard-kpp-bypass.html