The dc_chat function in cmd.dc.c in DConnect Daemon 0.7.0 and earlier allows remote attackers to cause a denial of service (application crash) by sending a client message before providing the nickname, which triggers a null pointer dereference.
https://exchange.xforce.ibmcloud.com/vulnerabilities/28279
http://www.vupen.com/english/advisories/2006/3181
http://www.securityfocus.com/archive/1/442440/100/0/threaded