1) Change milw0rm.com to your domain.com
2) Post the below code into a new message.
Credits to Nick Griffin.
# milw0rm.com [2005-07-14]
e107 contains a flaw that allows a remote cross site scripting attack. This flaw exists because the application does not validate [url] BBCode tags upon submission to the system. 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.
Currently, there are no known upgrades, patches, or workarounds available to correct this issue.