PHP remote file inclusion vulnerability in tell_a_friend.inc.php for Tell A Friend Script 2.7 before 20050305 allows remote attackers to execute arbitrary PHP code by modifying the script_root parameter to reference a URL on a remote web server that contains the code. NOTE: it was later reported that 2.4 is also affected.
https://exchange.xforce.ibmcloud.com/vulnerabilities/19630
http://www.stadtaus.com/forum/t-1579.html
http://www.stadtaus.com/forum/t-1578.html
http://www.securityfocus.com/archive/1/474954/100/0/threaded