libxml2 security update

CentOS Errata and Security Advisory CESA-2013:0581

The libxml2 library is a development toolbox providing the implementation
of various XML standards.

A denial of service flaw was found in the way libxml2 performed string
substitutions when entity values for entity references replacement was
enabled. A remote attacker could provide a specially-crafted XML file that,
when processed by an application linked against libxml2, would lead to
excessive CPU consumption. (CVE-2013-0338)

All users of libxml2 are advised to upgrade to these updated packages,
which contain a backported patch to correct this issue. The desktop must
be restarted (log out, then log back in) for this update to take effect.

Merged security bulletin from advisories:
https://lists.centos.org/pipermail/centos-announce/2013-March/081422.html
https://lists.centos.org/pipermail/centos-announce/2013-March/081789.html
https://lists.centos.org/pipermail/centos-cr-announce/2013-March/027083.html

Affected packages:
libxml2
libxml2-devel
libxml2-python
libxml2-static

Upstream details at:
https://access.redhat.com/errata/RHSA-2013:0581