Tainted input detected to an unserialize call.
Passing untrusted user input to unserialize calls is dangerous – from the PHP documentation on unserialize:
Do not pass untrusted user input to unserialize() regardless of the options value of allowed_classes. Unserialization can result in code being loaded and executed due to object instantiation and autoloading, and a malicious user may be able to exploit this. Use a safe, standard data interchange format such as JSON (via json_decode() and json_encode()) if you need to pass serialized data to the user.
<?php
$command = $_GET["data"];
getObject($command);
function getObject(string $data) : object {
return unserialize($data);
}