"EFnet member Fionn 'Fudge' Kelleher reported several vulnerabilities in the IRC daemons charybdis, ircd-ratbox, and other derivative IRCds. The vulnerability was subsequently used to bring down large portions of the EFnet IRC network."By crafting a particular message, you can cause the IRC daemon to call strlen(NULL) and game over, core dumped.

http://tech.slashdot.org/story/12/12...-vulnerability