footer.php in PunBB 1.2.14 and earlier allows remote attackers to include local files in include/user/ via a cross-site scripting (XSS) attack, or via the pun_include tag, as demonstrated by use of admin_options.php to execute PHP code from an uploaded avatar file.
http://www.vupen.com/english/advisories/2007/1362
http://www.securityfocus.com/archive/1/465400/100/100/threaded
http://www.securityfocus.com/archive/1/465338/100/100/threaded
http://www.acid-root.new.fr/advisories/13070411.txt
http://securityreason.com/securityalert/2613