Heap-based buffer overflow in XChat 2.8.9 and earlier allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a long response string.
https://euvd.enisa.europa.eu/vulnerability/EUVD-2011-5029
http://www.securitytracker.com/id?1027468
http://www.securityfocus.com/bid/50820