Most exploits targeting Zend Engine v3.4.0 center on how the engine handles data types and memory allocation.
By overwriting a function pointer or the "vtable" of a PHP object, the attacker redirects execution flow. zend engine v3.4.0 exploit
Always update PHP to the latest stable version to receive security headers and engine fixes. Most exploits targeting Zend Engine v3
The internal data structure used by the Zend Engine to represent any variable in PHP. Serialization/Unserialization: zend engine v3.4.0 exploit
The vulnerability is caused by a use-after-free bug, which occurs when the zend_string_extend function is called on a string that has already been freed. This can happen when a string is modified concurrently by multiple threads, or when a string is freed prematurely.