> the loader can allow part of that application's data segment to map over the memory area reserved for its stack resulting in corruption of the stack, with possible privilege escalation So if you can craft and execute an executable, and you can write to things that you already have write access to, how does that result in a privilege escalation? If you could overlap with things you shouldn't be able to access, e.g.…
https://www.qualys.com/2017/06/19/stack-clash/stack-clash.tx... might help understand the exploitation method.