ircu 2.10.12.02 through 2.10.12.04 allows remote attackers to cause a denial of service (memory and bandwidth consumption) by creating a large number of unused channels (zannels).
https://exchange.xforce.ibmcloud.com/vulnerabilities/35988
http://www.securityfocus.com/bid/25285
http://www.securityfocus.com/archive/1/476285/100/0/threaded