NRPE metacharacter filtering omission (important)

NRPE (the Nagios Remote Plug-In Executor) allows the
passing of $() to plugins/scripts which, if run under bash,
will execute that shell command under a subprocess and pass
the output as a parameter to the called script. Using this,
it is possible to get called scripts, such as check_http,
to execute arbitrary commands under the uid that
NRPE/nagios is running as (typically, ‘nagios’).

With this update NRPE will deny remote requests
containing a bash command substitution.