Russ McRee has discovered some vulnerabilities in WebCalendar, which can be exploited by malicious people to conduct cross-site scripting attacks.

1) Input passed to the "tab" parameter in users.php is not properly sanitised before being returned to the user. This can be exploited to execute arbitrary HTML and script code in a user's browser session in context of an affected site.

2) Input appended to the URL after day.php, month.php, and week.php is not properly sanitised before being returned to the user. This can be exploited to execute arbitrary HTML and script code in a user's browser session in context of an affected site.

The vulnerabilities are confirmed in version 1.2.0. Other versions may also be affected.

Solution
Update to version 1.2.5.

Provided and/or discovered by
Russ McRee via Secunia.

Changelog
Further details available to Secunia VIM customers

Original Advisory
WebCalendar:
http://sourceforge.net/mailarchive/forum.php?thread_name=z2u1f9585051004090711qf8e317e5k1b4ac0470131a93a%40mail.gmail.com&forum_name=webcalendar-announce
http://webcalendar.cvs.sourceforge.net/viewvc/webcalendar/webcalendar/ChangeLog?pathrev=REL_1_2

Russ McRee:
http://holisticinfosec.org/content/view/133/45/

Other references
Further details available to Secunia VIM customers

Deep Links
Links available to Secunia VIM customers