PHP remote file inclusion vulnerability in (1) about.php or (2) auth.php in TotalCalendar allows remote attackers to execute arbitrary PHP code via a URL in the inc_dir parameter.
http://www.vupen.com/english/advisories/2006/1418
http://www.securityfocus.com/bid/17618
http://sweetphp.com/files/downloads/patches/TotalCalendar/Security_Patch.zip
http://secunia.com/advisories/19730
http://pridels0.blogspot.com/2006/04/totalcalendar-remote-code-execution.html