[kevingadd]

Windows NT (and as a result win2k, xp, 7, 8, and 10) has always had strict user and kernel space separation. Modern Windows also has separate 'integrity levels' within user space - for example, Chrome and Firefox run most of their functionality at 'Low' integrity to prevent compromised browser code from being used to exploit other processes. I'm not sure what the basis is for the claims you're making about the kernel. The idea that distinguishing between kernel and user code is Not Allowed is very confusing to me, how would you do that without running both user and kernel code at the same privilege level in a shared address space?

The CVE here literally has nothing to do with privilege separation or being unable to distinguish between user mode and kernel mode. It's this simple:

* Someone in user-space wanted to parse an executable to get information on it

* A syscall is exposed to parse an executable

* They used the syscall to parse the executable, and that code path had a bug in it which triggered a BSOD (since the failure was in kernel mode).

In the end, this is just "a syscall had a bug in it that caused a kernel crash, and a user-mode application issued the syscall on mouse-over".