I hesitate to say, because there's a possibility that even years later many of the vulnerabilities are still there.
However, one that I know eventually got fixed I'll talk about (it makes a great example anyway). When port scanning one of our pieces of equipment, I noticed a strange port number that was accepting packets. I started sending random packets to it and for the most part it ignored them, but occasionally I could get the system to crash and restart.
Turns out, the server had a debug port enabled and active, even in the production build. This allowed you to essentially invoke any C function you wanted, remotely, if you knew the format (which was published in the OS manual)! Very, very bad.
When I reported it, I got a lot of responses like, "Well, this will be on a closed net anyway." and "If they get on this network, there's much bigger problems." Both statements were true for the most part, but still a very dangerous attitude to have. Just because a network compromise would be bad, doesn't mean you should make it worse by neglecting defense-in-depth. And never assume that somebody isn't going to plug an ethernet cable into your equipment that shouldn't be there (this happens all the time).