TikiWiki CMS/Groupware 8.3 and earlier allows remote attackers to obtain the installation path via a direct request to (1) admin/include_calendar.php, (2) tiki-rss_error.php, or (3) tiki-watershed_service.php.
http://info.tiki.org/article191-Tiki-Releases-8-4
http://info.tiki.org/article190-Tiki-Wiki-CMS-Groupware-Updates-Tiki-6-7-LTS