ejabberd, when expat is used, do not properly detect recursion during entity expansion, which allows context-dependent attackers to cause a denial of service (memory and CPU consumption) via a crafted XML document containing a large number of nested entity references, aka the "billion laughs attack." References: [1] http://en.wikipedia.org/wiki/Billion_laughs [2] http://www.ibm.com/developerworks/xml/library/x-tipcfsx/
This issue affects the versions of the ejabberd package, as present within EPEL-5 and EPEL-6 repositories. This issue affects the versions of the ejabberd package, as shipped with Fedora release of 13 and 14.
The CVE identifier of CVE-2011-1753 has been assigned to this issue.
Public now via: http://www.ejabberd.im/ejabberd-2.1.7
The fix for this issue has been already included in the following updates: 1) ejabberd-2.1.8-1.el6 for EPEL-6, 2) ejabberd-2.1.8-1.el5 for EPEL-5, 3) ejabberd-2.1.8-1.fc15 for Fedora-15 and finally 4) ejabberd-2.1.8-1.fc14 for Fedora-14.
(In reply to comment #6) > The fix for this issue has been already included in the following updates: > 1) ejabberd-2.1.8-1.el6 for EPEL-6, > 2) ejabberd-2.1.8-1.el5 for EPEL-5, > 3) ejabberd-2.1.8-1.fc15 for Fedora-15 and finally > 4) ejabberd-2.1.8-1.fc14 for Fedora-14. Note - I don't plan to update F-13 (it will be obsoleted very soon so why bother).