ngIRCd 0.10.x before 0.10.4 and 0.11.0 before 0.11.0-pre2 allows remote attackers to cause a denial of service (crash) via crafted IRC PART message, which triggers an invalid dereference.
irc-channel.c in ngIRCd before 0.10.3 allows remote attackers to cause a denial of service (crash) via a JOIN command without a channel argument.