After installing KB5005076 on Windows Server 2012 R2 (or any of the cumulative security updates that follow it as they include this update), IIS application pools which are set to allow 32 bit mode begin to crash, writing BEX errors (Buffer Overflow Exception) to the event log, referencing either w3wp or regsvr32 as the faulting process.
Uninstalling this KB/security patch (or running all IIS pools in 64 bit mode) will fix the issue. As to why this is an issue I am unsure at this time, but wanted to share this in case others are having this issue as there didn't seem to be any information out there about this possible link yet.
Faulting application name: w3wp.exe, version: 8.5.9600.16384, time stamp:
Faulting module name: ntdll.dll, version: 6.3.9600.20090, time stamp: Dx60eg12D8
Exception code: 0xc000005
Fault offset: 0x0002a8c0
Faulting application path: C:\Windows\SYSWOW64\inetsrv\w3wp.exe
Faulting module path: C:\Windows\SYSTEM32\ntdll.dll
I will update this as more information comes to light.