The IRC script included in Light 2.7.x before 2.7.30p5, and 2.8.x before 2.8pre10, running EPIC allows remote attackers to execute arbitrary code if the user joins a channel whose topic includes EPIC4 code.
http://www.securityfocus.com/bid/5555
http://www.iss.net/security_center/static/9943.php
http://www.debian.org/security/2002/dsa-156
http://archives.neohapsis.com/archives/bugtraq/2002-08/0231.html