The remote host is missing an update to mhonarc announced via advisory DSA 163-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%20163-1

Jason Molenda and Hiromitsu Takagi found ways to exploit cross site scripting bugs in mhonarc, a mail to HTML converter. When processing maliciously crafted mails of type text/html, mhonarc, does not deactivate all scripting parts properly. This is fixed in upstream version 2.5.3. If you are worried about security, it is recommended that you disable support of text/html messages in your mail archives. There is no guarantee that the mhtxthtml.pl library is robust enough to eliminate all possible exploits that can occur with HTML data. To exclude HTML data, you can use the MIMEEXCS resource. For example: <MIMEExcs> text/html text/x-html </MIMEExcs> The use of text/x-html is probably not used any more, but is good to include it, just-in-case. If you are concerend that this could block out the entire contents of some messages, then you could do the following instead: <MIMEFilters> text/html m2h_text_plain::filter mhtxtplain.pl text/x-html m2h_text_plain::filter mhtxtplain.pl </MIMEFilters> This treats the HTML as text/plain. The above problems have been fixed in version 2.5.2-1.1 for the current stable stable distribution (woody), in version 2.4.4-1.1 for the old stable distribution (potato) and in version 2.5.11-1 for the unstable distribution (sid). We recommend that you upgrade your mhonarc packages.