Over the last two months, some OpenBSD users noticed that the X server was crashing occasionally. Two bugs have been diagnosed and fixed by us. One was a use-after free bug in the X shared library linker. The other was a buffer-over-read bug deep down in the very lowest level fb* pixmap compositing routines. The latter bug in particular was very difficult to diagnose and fix, and is about 10 years old. We have found other bugs like this in other external software, and even a few in the base OpenBSD tree (though those were found a while back, even as we started experimenting with the new malloc code).
This is amazing. Bugs are detected in software packages that are 10 years old, in software that might be even older. I wonder if something like this can be brought in to OS X?