A friend just forwarded this URL to me:
http://pridels.blogspot.com/2006/03/mantis-xss-vuln.html

Quote:

###############################################
Vuln. discovered by : r0t
Date: 31 march 2006
vendor:http://www.mantisbt.org/
affected versions:Mantis 1.0.1 and 1.0.0rc5 and prior
###############################################

Vuln. Description:

Mantis contains a flaw that allows a remote cross site scripting attack. This
flaw exists because input passed to "start_day" "start_year" "start_month"
paremeters in "view_all_set.php" isn't properly sanitised before being returned
to the user.
This could allow a user to create a specially crafted URL that would execute
arbitrary code in a user's browser within the trust relationship between the
browser and the server, leading to a loss of integrity.

examples:

/view_all_set.php?type=1&temporary=y&do_filter_by_date
=on&start_year=2006&start_month=03&start_day=[XSS]

/view_all_set.php?type=1&temporary=y&do_filter_by_date=
on&start_year=[XSS]

/view_all_set.php?type=1&temporary=y&do_filter_by_date
=on&start_year=2006&start_month=[XSS]

###############################################
Solution:
Edit the source code to ensure that input is properly sanitised.
###############################################
More information @ unsecured-systems.com/forum/