The grapheme_stripos function in ext/intl/grapheme/grapheme_string.c in PHP before 5.5.35, 5.6.x before 5.6.21, and 7.x before 7.0.6 allows remote attackers to cause a denial of service (out-of-bounds read) or possibly have unspecified other impact via a negative offset.<a href=http://cwe.mitre.org/data/definitions/125.html>CWE-125: Out-of-bounds Read</a> http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2016-4540
