Direct static code injection vulnerability in the modify_config action in admin.php for PHP-Stats 0.1.9.1 and earlier allows remote authenticated administrators to execute arbitrary PHP code via the option_new[compatibility_mode] parameter, which is not filtered before being stored in config.php. NOTE: this vulnerability can be exploited by remote unauthenticated attackers in conjunction with the option[admin_pass] authentication bypass vulnerability.
http://www.vupen.com/english/advisories/2006/0822
http://www.securityfocus.com/bid/16963
http://www.securityfocus.com/archive/1/429145/100/0/threaded
http://www.securityfocus.com/archive/1/428614/100/0/threaded
http://www.securityfocus.com/archive/1/426762/100/0/threaded