Typing "IİI" (http://pastebin.com/nD0XkEsC) in chat will crash almost all of connected clients to the server, that receive the message. Some clients don't crash and i couldn't figure out why, but 95% will. Here is the error you get when you crash: http://pastebin.com/j3YXdQ4R (updated) Edit: Server log has this error: http://pastebin.com/K1cqKSGu Edit2: I just reliazed that when you paste this string ("İ") into Notepad++ is becomes two characters instead of one. So the String Index Out of Bounds error makes sense. The string "İ" takes up 1 space in game, and 2 spaces in notepad++. Edit3: Thanks to md_5 we figured that this happens only with client that run on Turkish Windows. Right now the only temporary fix is to block sending this string, with a chat filter plugin, such as PwnFilter.