ELA-166-1 libpng security update

fix for null pointer dereference

Related CVEs CVE-2016-10087

Patrick Keshishian found a null pointer dereference in a function of libpng, a library to handle PNG files.

For Debian 7 Wheezy, these problems have been fixed in version 1.2.49-1+deb7u3.

We recommend that you upgrade your libpng packages.

Further information about Extended LTS security advisories can be found at: https://deb.freexian.com/extended-lts/