Detection of an active exploit is harder. Look for:
Version of the Zend Engine is a specific, historical milestone. Bundled with PHP 7.4.x, it represented a leap forward in performance (via opcache preloading) and memory management. But with new features come new attack surfaces. While no widespread "click-and-exploit" remote code execution (RCE) vulnerability is uniquely labeled "Zend Engine v3.4.0 Exploit" (vulnerabilities are typically patched in PHP releases), understanding how to theoretically exploit memory corruption bugs within this specific engine version is a rite of passage for security researchers. zend engine v3.4.0 exploit
typedef union _zend_value zend_long lval; // long integer double dval; // double zend_refcounted *counted; // strings, arrays, objects zend_string *str; zend_array *arr; zend_object *obj; // ... zend_value; Detection of an active exploit is harder