The gdImageCrop function in ext/gd/gd.c in PHP 5.5.x before 5.5.9 does not check return values, which allows remote attackers to cause a denial of service (application crash) or possibly have unspecified other impact via invalid imagecrop arguments that lead to use of a NULL pointer as a return value, a different vulnerability than CVE-2013-7226.
https://bugzilla.redhat.com/show_bug.cgi?id=1065108
https://bugs.php.net/bug.php?id=66356
http://www.ubuntu.com/usn/USN-2126-1
http://git.php.net/?p=php-src.git%3Ba=commit%3Bh=8f4a5373bb71590352fd934028d6dde5bc18530b