ext/curl/interface.c in PHP 7.x before 7.0.10 does not work around a libcurl integer overflow, which allows remote attackers to cause a denial of service (allocation error and heap-based buffer overflow) or possibly have unspecified other impact via a long string that is mishandled in a curl_escape call.
https://security.gentoo.org/glsa/201611-22
https://github.com/php/php-src/commit/72dbb7f416160f490c4e9987040989a10ad431c7?w=1
https://bugs.php.net/bug.php?id=72674
http://www.securitytracker.com/id/1036680
http://www.securityfocus.com/bid/92766