libxml2 security update

CentOS Errata and Security Advisory CESA-2012:0016

The libxml2 library is a development toolbox providing the implementation
of various XML standards. One of those standards is the XML Path Language
(XPath), which is a language for addressing parts of an XML document.

A heap-based buffer overflow flaw was found in the way libxml2 decoded
entity references with long names. A remote attacker could provide a
specially-crafted XML file that, when opened in an application linked
against libxml2, would cause the application to crash or, potentially,
execute arbitrary code with the privileges of the user running the
application. (CVE-2011-3919)

An off-by-one error, leading to a heap-based buffer overflow, was found in
the way libxml2 parsed certain XML files. A remote attacker could provide a
specially-crafted XML file that, when opened in an application linked
against libxml2, would cause the application to crash or, potentially,
execute arbitrary code with the privileges of the user running the
application. (CVE-2011-0216)

A flaw was found in the way libxml2 parsed certain XPath expressions. If an
attacker were able to supply a specially-crafted XML file to an application
using libxml2, as well as an XPath expression for that application to run
against the crafted file, it could cause the application to crash.
(CVE-2011-2834)

Note: Red Hat does not ship any applications that use libxml2 in a way that
would allow the CVE-2011-2834 flaw to be exploited; however, third-party
applications may allow XPath expressions to be passed which could trigger
this flaw.

An out-of-bounds memory read flaw was found in libxml2. A remote attacker
could provide a specially-crafted XML file that, when opened in an
application linked against libxml2, would cause the application to crash.
(CVE-2011-3905)

All users of libxml2 are advised to upgrade to these updated packages,
which contain backported patches to correct these issues. 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-January/080531.html

Affected packages:
libxml2
libxml2-devel
libxml2-python

Upstream details at:
https://access.redhat.com/errata/RHSA-2012:0016