Is Quicksort a potential security risk?

Question

I just wondered whether (with some serious paranoia and under certain circumstances) the use of the QuickSort algorithm can be seen as a security risk in an application

Answer 1

It is, but only in very, very unlikely cases -- all of which are easy for a properly-designed algorithm to avoid.

But if you want to be super-safe, you may want to use something like Introsort, which starts out as QuickSort but switches over to Heap Sort if it detects from the recursion depth that the algorithm is starting to go quadratic.

Edit: I see Pavel beat me to Introsort.

In Response to Edited Question: I haven't personally tested every single Quicksort library, but I feel safe betting that pretty much all of them have checks in place to avoid the worst case.