CVE-2026-37552: Unsafe deserialization vulnerability in MixPHP Framework 2

Unsafe deserialization vulnerability in MixPHP Framework 2.x thru 2.2.17. The sync-invoke TCP server (Server.php:87) receives data from a TCP socket, passes it directly to Opis\Closure\unserialize(), then executes the result via call_user_func(). No authentication or signature verification exists on the TCP connection. An attacker with access to the localhost TCP port (server binds 127.0.0.1) can send a crafted serialized PHP closure to achieve arbitrary code execution.