For those of you who are avid IRC users I thought I would throw out the fact that there is a big exploit in versions 6.* up to and not including 6.12. What this included and allowed was

Starting Oct 12, 2003, an exploit was used to crash many people's mIRC clients. All versions from 6.0 thru 6.11 were affected, 6.12 was released Oct 13 to fix the problem. The exploit involves a DCC command which can be sent to any person or channel, no matter what your DCC options are. (DCC is used to trade files or for DCC chat.) You can either download the new version (and hope it has no new bugs), or if you can afford to wait a few days, maybe stick to the old temporary fix of ignoring all DCC sends entirely. Just type the following command, on a new line by itself in any chat window, beginning with the slash character:

/ignore -wd *
Source

What it would do is crash your version of IRC and give it a critical error, but also opened you up for Buffer overflows. there has been a new version of mIRC released that you can get here

Hope this helps and keeps those holes patched