centericq 4.20.0-r3 with "Enable peer-to-peer communications" set allows remote attackers to cause a denial of service (segmentation fault and crash) via short zero-length packets, and possibly packets of length 1 or 2, as demonstrated using Nessus.
https://exchange.xforce.ibmcloud.com/vulnerabilities/23327
https://bugs.gentoo.org/show_bug.cgi?id=100519
http://www.securityfocus.com/bid/15649
http://www.debian.org/security/2005/dsa-912
http://security.gentoo.org/glsa/glsa-200512-11.xml
http://secunia.com/advisories/18081
http://secunia.com/advisories/17818