PHP remote file inclusion vulnerability in includes/config.php in WebCalendar 1.0.3 allows remote attackers to execute arbitrary PHP code via a URL in the includedir parameter, which is remotely accessed in an fopen call whose results are used to define a user_inc setting that is used in an include_once call.
http://www.vupen.com/english/advisories/2006/2067
http://www.securityfocus.com/bid/18175
http://www.securityfocus.com/archive/1/436263/100/0/threaded
http://www.securityfocus.com/archive/1/435379
http://www.debian.org/security/2006/dsa-1096
http://securitytracker.com/id?1016179
http://securityreason.com/securityalert/1019