Multiple buffer overflows in BitchX IRC client 1.0-0c19 and earlier allow remote malicious IRC servers to cause a denial of service (crash) and possibly execute arbitrary code via long hostnames nicknames or channel names which are not properly handled by the functions (1) send_ctcp (2) cannot_join_channel (3) cluster (4) BX_compress_modes (5) handle_oper_vision and (6) ban_it.