lib/rrd.php in Cacti 1.1.27 allows remote authenticated administrators to execute arbitrary OS commands via the pathrrdtool parameter in an action=save request to settings.php.

Cacti 1.1.27 allows remote authenticated administrators to conduct Remote Code Execution attacks by placing the Log Path under the web root, and then making a remoteagent.php request containing PHP code in a Client-ip header.

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.