The remote host is missing an update to ejabberd announced via advisory DSA 2248-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%202248-1

Wouter Coekaerts discovered that ejabberd, a distributed XMPP/Jabber server written in Erlang, is vulnerable to the so-called billion laughs attack because it does not prevent entity expansion on received data. This allows an attacker to perform denial of service attacks against the service by sending specially crafted XML data to it. For the oldstable distribution (lenny), this problem has been fixed in version 2.0.1-6+lenny3. For the stable distribution (squeeze), this problem has been fixed in version 2.1.5-3+squeeze1. For the testing distribution (wheezy), this problem will be fixed soon. For the unstable distribution (sid), this problem has been fixed in version 2.1.6-2.1. We recommend that you upgrade your ejabberd packages.