/usr/lib/cgi-bin/nagios3/graphs.cgi is in nagiosgrapher 1.7.1-3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/cgi-bin/nagios3/../nagiosgrapher/graphs.cgi
/usr/lib/cgi-bin/nagios3/../nagiosgrapher/graphs.cgi