[SECURITY] [DLA 691-1] libxml2 security update

Package : libxml2
Version : 2.8.0+dfsg1-7+wheezy7
CVE ID : CVE-2016-4658 CVE-2016-5131

CVE-2016-4658
Namespace nodes must be copied to avoid use-after-free errors.
But they don't necessarily have a physical representation in a
document, so simply disallow them in XPointer ranges.

CVE-2016-5131
The old code would invoke the broken xmlXPtrRangeToFunction.
range-to isn't really a function but a special kind of
location step. Remove this function and always handle range-to
in the XPath code.
The old xmlXPtrRangeToFunction could also be abused to trigger
a use-after-free error with the potential for remote code
execution.

For Debian 7 "Wheezy", these problems have been fixed in version
2.8.0+dfsg1-7+wheezy7.

We recommend that you upgrade your libxml2 packages.

Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://wiki.debian.org/LTS