Multiple format string vulnerabilities in lib/silcclient/command.c in Secure Internet Live Conferencing (SILC) Toolkit before 1.1.10 and SILC Client 1.1.8 and earlier allow remote attackers to execute arbitrary code via format string specifiers in a channel name related to (1) silc_client_command_topic (2) silc_client_command_kick (3) silc_client_command_leave and (4) silc_client_command_users.