Prosody before 0.9.4 does not properly restrict the processing of compressed XML elements, which allows remote attackers to cause a denial of service (resource consumption) via a crafted XMPP stream, aka an "xmppbomb" attack, related to core/portmanager.lua and util/xmppstream.lua.
http://www.debian.org/security/2014/dsa-2895
http://secunia.com/advisories/57710
http://openwall.com/lists/oss-security/2014/04/09/1
http://openwall.com/lists/oss-security/2014/04/07/7
http://hg.prosody.im/0.9/rev/a97591d2e1ad