The remote host is missing an update to mailman announced via advisory DSA 147-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%20147-1

A cross-site scripting vulnerability was discovered in mailman, a software to manage electronic mailing lists. When a properly crafted URL is accessed with Internet Explorer (other browsers don't seem to be affected), the resulting webpage is rendered similar to the real one, but the javascript component is executed as well, which could be used by an attacker to get access to sensitive information. The new version for Debian 2.2 also includes backports of security related patches from mailman 2.0.11. This problem has been fixed in version 2.0.11-1woody2 for the current stable distribution (woody), in version 1.1-10.1 for the old stable distribution (woody) and in version 2.0.12-1 for the unstable distribution (sid). We recommend that you upgrade your mailman package.