(RHSA-2011:0858) Moderate: xerces-j2 security update

The xerces-j2 packages provide the Apache Xerces2 Java Parser, a
high-performance XML parser. A Document Type Definition (DTD) defines the
legal syntax (and also which elements can be used) for certain types of
files, such as XML files.

A flaw was found in the way the Apache Xerces2 Java Parser processed the
SYSTEM identifier in DTDs. A remote attacker could provide a
specially-crafted XML file, which once parsed by an application using the
Apache Xerces2 Java Parser, would lead to a denial of service (application
hang due to excessive CPU use). (CVE-2009-2625)

Users should upgrade to these updated packages, which contain a backported
patch to correct this issue. Applications using the Apache Xerces2 Java
Parser must be restarted for this update to take effect.