alt Hacker NewsThere was a Windows 2000 bug that would allow the computer to be crashed via a malformed IrDA packet. Of course someone crafted a Palm Pilot app to zonk all the vulnerable PCs in the vicinity. It worked on servers as well. Endless fun for a little while.
And of course the Ping of Death (which I thought was windows-only, but according to the linked article also affected linux and mac).
[0] https://en.wikipedia.org/wiki/Ping_of_death