Resin contains a flaw that allows a remote cross site scripting attack. This flaw exists because the application does not validate user input upon submission to the Java Servlet which is in turn passed to the error handler. 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.
Upgrade to version 1.2.4 or higher, as it has been reported to fix this vulnerability. It is also possible to temporarily work around the flaw by implementing the following workaround: Customize error pages.