Multiple stack-based buffer overflows in FSD 2.052 d9 and earlier, and FSFDT FSD 3.000 d9 and earlier, allow (1) remote attackers to execute arbitrary code via a long HELP command on TCP port 3010 to the sysuser::exechelp function in sysuser.cc and (2) remote authenticated users to execute arbitrary code via long commands on TCP port 6809 to the servinterface::sendmulticast function in servinterface.cc, as demonstrated by a PIcallsign command.