Cisco Jabber Extensible Communications Platform (aka Jabber XCP) 2.x through 5.4.x before 5.4.0.27581 and 5.8.x before 5.8.1.27561 does not properly detect recursion during entity expansion, which allows remote attackers to cause a denial of service (memory and CPU consumption, and process crash) via a crafted XML document containing a large number of nested entity references, aka Bug ID CSCtq78106, a similar issue to CVE-2003-1564.