Variable overwrite vulnerability in David Bennett PHP-Post (PHPp) 1.0 and earlier allows remote attackers to overwrite arbitrary program variables via multiple vectors that use the extract function, as demonstrated by the table_prefix parameter in (1) index.php, (2) profile.php, and (3) header.php.
http://www.vupen.com/english/advisories/2006/3688
http://www.securityfocus.com/bid/20061
http://www.securityfocus.com/archive/1/446318/100/0/threaded