While technically a framework-level issue, exploits like CVE-2021-3007 leverage the way the Zend Engine handles object deserialization to achieve RCE.
Attackers often target the Zend Engine to bypass security restrictions like disable_functions or open_basedir . By exploiting a memory corruption bug within the engine, an attacker can gain "godmode" access, potentially leading to a root shell if the process (e.g., Apache with mod_php ) is misconfigured. Recent Vulnerability Trends (2025–2026) zend engine v3.4.0 exploit
An issue in php_request_shutdown that causes a Use-After-Free, primarily affecting PHP 8.3 and 8.4 but highlighting persistent logic risks in the Zend core. Critical Vulnerability Vectors in Zend Engine v3
A critical vulnerability found in ZendTo (up to 6.10-6) where manipulation of file arguments leads to remote command injection. While technically a framework-level issue
However, because Zend Engine 3.4.0 is used by a vast number of web applications, it remains a primary target for security researchers and malicious actors seeking to exploit core memory management or engine-level vulnerabilities. Critical Vulnerability Vectors in Zend Engine v3.4.0