channel.c in ngIRCd 20 and 20.1 allows remote attackers to cause a denial of service (assertion failure and crash) via a KICK command for a user who is not on the associated channel.

The (1) ConnGetCipherInfo and (2) ConnUsesSSL functions in src/ngircd/conn.c in ngIRCd 13 and 14, when SSL/TLS support is present and standalone mode is disabled, allow remote attackers to cause a denial of service (application crash) by sending the MOTD command from another server in the same IRC network, possibly related to an array index error.

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.

Integer underflow in the ListsMakeMask() function in lists.c in ngIRCd before 0.8.2 allows remote attackers to cause a denial of service (application crash) and possibly execute arbitrary code via a long MODE line that causes an incorrect length calculation, which leads to a buffer overflow.

Format string vulnerability in the LogResolver function in log.c for ngIRCd 0.8.2 and earlier, when compiled with IDENT, logging to SYSLOG, and with DEBUG enabled, allows remote attackers to execute arbitrary code.