Cacti 1.1.27 allows remote authenticated administrators to read arbitrary files by placing the Log Path into a private directory, and then making a clog.php?filename= request, as demonstrated by filename=passwd (with a Log Path under /etc) to read /etc/passwd.
lib/rrd.php in Cacti 1.1.27 allows remote authenticated administrators to execute arbitrary OS commands via the path_rrdtool parameter in an action=save request to settings.php.