[davidtgoldblatt]

Oh yes; while certainly mismatched new[]/delete has been a source of problems since forever, what I mean specifically is the new types of exploits possible with the "operator delete(void* ptr, size_t sz)" overload (and its array cousin).

Before C++14, using delete (rather than delete[]) to deallocate an array of ints (or other trivially destructible data types) would be safe in practice, even though it was disallowed. In a world with sized deallocation functions, it's exploitable.