Source : Free On-Line Dictionary of Computing

smash the stack
     
         In {C} programming, to corrupt the execution stack by
        writing past the end of a local array or other data structure.
        Code that smashes the stack can cause a return from the
        routine to jump to a random address, resulting in insidious
        data-dependent {bug}s.
     
        Variants include "trash" the stack, {scribble} the stack,
        {mangle} the stack.
     
        See {spam}; see also {aliasing bug}, {fandango on core},
        {memory leak}, {memory smash}, {precedence lossage}, {overrun
        screw}.
     
        [{Jargon File}]
     
        (1995-03-16)