Integer overflow in the php_escape_html_entities_ex function in ext/standard/html.c in PHP before 5.5.36 and 5.6.x before 5.6.22 allows remote attackers to cause a denial of service or possibly have unspecified other impact by triggering a large output string from a FILTER_SANITIZE_FULL_SPECIAL_CHARS filter_var call.  NOTE: this vulnerability exists because of an incomplete fix for CVE-2016-5094.