Cacti 0.8.6e and earlier does not perform proper input validation to protect against common attacks, which allows remote attackers to execu…

Cacti 0.8.6e and earlier does not perform proper input validation to protect against common attacks, which allows remote attackers to execute arbitrary commands or SQL by sending a legitimate value in a POST request or cookie, then specifying the attack string in the URL, which causes the get_request_var function to return the wrong value in the $_REQUEST variable, which is cleansed while the original malicious $_GET value remains unmodified, as demonstrated in (1) graph_image.php and (2) graph.php.