Possible buffer read overflow was fixed upstream [1]. This was also reported against PHP: https://bugs.php.net/bug.php?id=68601 (bug is private, fixed in PHP 5.6.5) [1]: https://bitbucket.org/libgd/gd-libgd/commits/47eb44b2e90ca88a08dca9f9a1aa9041e9587f43
PHP Commits http://git.php.net/?p=php-src.git;a=commitdiff;h=07b5896a1389c3e865cbd2fb353806b2cefe4f5c http://git.php.net/?p=php-src.git;a=commitdiff;h=5fc2fede9c7c963c950d8b96dcc0f7af88b4d695
Fixed in 5.5.21 and 5.6.5
This issue has been addressed in the following products: Red Hat Software Collections for Red Hat Enterprise Linux 7 Red Hat Software Collections for Red Hat Enterprise Linux 6 Red Hat Software Collections for Red Hat Enterprise Linux 6.6 EUS Red Hat Software Collections for Red Hat Enterprise Linux 6.5 EUS Via RHSA-2015:1066 https://rhn.redhat.com/errata/RHSA-2015-1066.html
This issue has been addressed in the following products: Red Hat Software Collections for Red Hat Enterprise Linux 7 Red Hat Software Collections for Red Hat Enterprise Linux 6 Red Hat Software Collections for Red Hat Enterprise Linux 6.6 EUS Red Hat Software Collections for Red Hat Enterprise Linux 6.5 EUS Via RHSA-2015:1053 https://rhn.redhat.com/errata/RHSA-2015-1053.html
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2015:1135 https://rhn.redhat.com/errata/RHSA-2015-1135.html
This issue has been addressed in the following products: Red Hat Enterprise Linux 6 Via RHSA-2015:1218 https://rhn.redhat.com/errata/RHSA-2015-1218.html