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.

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.

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.