Recently a exploit to a newly found buffer overflow in mIRC has been ben written and posten on securiteam.com. The shellcode only executes cmd.exe but can easily be modified to do anything else. mIRC does not even have to be runing for this exploit to work, as long as it is installed on the computer. I give it a few more days before somebody comes out with a script kiddie friendly version of the exploit. IRC may never be safe again, at least for you Windows users, hehe. Here's a link to the article.