php_snmp_error() Format String Vulnerability

How it was found

PHP <= 7.0.4/5.5.34 contained a format string vulnerability in php_snmp_error() at ext/snmp/snmp.c:533, because snmp_object->snmp_errstr was passed directly to zend_throw_exception_ex() without a "%s". This issue appears to have been present across all PHP versions. In testing, I have been able to leverage this vulnerability for full code-execution by abusing PHP's internal "%Z" (zval) format specifier. In the interest of good ol' PoC, that exploit is attached. :)

This issue has been patched in PHP v7.0.5 https://bugs.php.net/bug.php?id=71704 https://secure.php.net/ChangeLog-7.php#7.0.5