The language makes all the difference because defaults matter. As someone said once, you can write C in any language. You can even do a heartbleed in python - just create one big buffer, do your own allocator, and pass (buffer, index) everywhere instead of proper object.
But would anyone do this? No. If you are writing pool-based packet processor in Python, you'd deal in buffers (safe from overread), in C# you'd return Span/Memory (safe from overread) and only in C you'd return overread-prone raw pointer.
Not that you can blame programmers in this case - C simply lacks the facilities for safe memory access, such as bounded pointers or spans. And you can't really blame it on custom allocator - malloc() would have had the same problem.
> only in C you'd return overread-prone raw pointer.
If that was all they did, tooling like valgrind and sanitisers would have caught it.
Heartbleed was an issue because they used their own allocator. If they didn't use their own allocator, the error (over-running an array/reusing deallocated memory) would have been caught by the tooling.
But would anyone do this? No. If you are writing pool-based packet processor in Python, you'd deal in buffers (safe from overread), in C# you'd return Span/Memory (safe from overread) and only in C you'd return overread-prone raw pointer.
Not that you can blame programmers in this case - C simply lacks the facilities for safe memory access, such as bounded pointers or spans. And you can't really blame it on custom allocator - malloc() would have had the same problem.