HeapAlloc isn't zero'ing memory from the heap before returning it when the HEAP_ZERO_MEMORY flag is passed.
https://learn.microsoft.com/en-us/windows/win32/api/heapapi/nf-heapapi-heapalloc
HEAP_ZERO_MEMORY 0x00000008 The allocated memory will be initialized to zero. Otherwise, the memory is not initialized to zero.
HeapAlloc isn't zero'ing memory from the heap before returning it when the HEAP_ZERO_MEMORY flag is passed.
https://learn.microsoft.com/en-us/windows/win32/api/heapapi/nf-heapapi-heapalloc