PHP remote file inclusion vulnerability in index.php in Knusperleicht Newsletter 3.5 and earlier allows remote attackers to execute arbitrary PHP code via a URL in the NL_PATH parameter.
https://www.exploit-db.com/exploits/2097
https://exchange.xforce.ibmcloud.com/vulnerabilities/28109
http://www.vupen.com/english/advisories/2006/3093
http://www.securityfocus.com/archive/1/441807/100/0/threaded