Cross-site scripting vulnerabilities in GeekLog 1.3.5 and earlier allow remote attackers to execute arbitrary script via (1) the url variable in the Link field of a calendar event, (2) the topic parameter in index.php, or (3) the title parameter in comment.php.
http://www.iss.net/security_center/static/9310.php
http://www.iss.net/security_center/static/9309.php
http://geeklog.sourceforge.net/article.php?story=20020610013358149
http://archives.neohapsis.com/archives/bugtraq/2002-06/0058.html