Faulting module name: ntdll.dll, version: 6.3.9600.19678 Exception code: 0xc0000005

I had a VC++ project (console application) built on VS2013. It was working successfully for a long time. Recently we have converted that project to VS2019 (PlatformToolset 142). Now the latest exe is crashing after some operation with below error.

Faulting application name: abc.exe, version: 0.0.0.0, time stamp: 0x5eb3101a Faulting module name: ntdll.dll, version: 6.3.9600.19678, time stamp: 0x5e82c88a Exception code: 0xc0000005 Fault offset: 0x0000000000030837 Faulting process id: 0x137c Faulting application start time: 0x01d624424de8d7e1 Faulting application path: Faulting module path: C:\Windows\SYSTEM32\ntdll.dll Report Id: 8bad3b06-9035-11ea-80de-d6b5b2fa72df Faulting package full name: Faulting package-relative application ID:

One big observation is VS2019 exe is half size of VS2013 exe. How to debug further to find out the root cause of the application crash?

After run-in remote debug found that it is throwing an unhandled exception at

HeapAlloc( m_hHeap, HEAP_NO_SERIALIZE, _Count * sizeof( value_type ));

This was working perfectly with VC2013. This HeapAlloc issue I am getting whenever we are calling std::vector related operation. Is anything got change related to this in VS2019/VC++2019 ?