The remote host is missing an update to the system as announced in the referenced advisory.

Update your system with the appropriate patches or software upgrades. http://www.ejabberd.im/ejabberd-2.1.7 http://www.vuxml.org/freebsd/01d3ab7d-9c43-11e0-bc0f-0014a5e3cda6.html

The following package is affected: ejabberd CVE-2011-1753 expat_erl.c in ejabberd before 2.1.7 and 3.x before 3.0.0-alpha-3, and exmpp before 0.9.7, does not properly detect recursion during entity expansion, which allows remote attackers to cause a denial of service (memory and CPU consumption) via a crafted XML document containing a large number of nested entity references, a similar issue to CVE-2003-1564.