I'd call it even likely, with most of the flat memory OSs of the past. We are talking 50 years ago.

C64 had a flat memory map, where the input came as the first address in range 0 to DFFF. What came after that? The kernel. So if you wrote too much data into the input address space, and the overflow wasn't caught, you'd overwrite the OS there, too. And writing into the IO table was common, because it was faster to access.