MEDIUM
ext/gd/gd.c in PHP 5.5.x before 5.5.9 does not check data types, which might allow remote attackers to obtain sensitive information by using a (1) string or (2) array data type in place of a numeric data type, as demonstrated by an imagecrop function call with a string for the x dimension value, a different vulnerability than CVE-2013-7226.
http://www.ubuntu.com/usn/USN-2126-1
https://bugs.php.net/bug.php?id=66356
https://github.com/php/php-src/commit/2938329ce19cb8c4197dec146c3ec887c6f61d01