libxml2 security update

CentOS Errata and Security Advisory CESA-2012:0324

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

It was found that the hashing routine used by libxml2 arrays was
susceptible to predictable hash collisions. Sending a specially-crafted
message to an XML service could result in longer processing time, which
could lead to a denial of service. To mitigate this issue, randomization
has been added to the hashing function to reduce the chance of an attacker
successfully causing intentional collisions. (CVE-2012-0841)

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/2012-February/080612.html

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

Upstream details at:
https://access.redhat.com/errata/RHSA-2012:0324