What are the potential security risks associated with the current upload script code?

The current upload script code does not have any validation or sanitization of user input, making it vulnerable to various security risks such as file injection attacks, malicious file uploads, and potential code execution. To mitigate these risks, input validation, file type checking, and file size limitations should be implemented. 

// Validate file type and size before uploading
$allowedFileTypes = ['jpg', 'jpeg', 'png', 'gif'];
$maxFileSize = 5 * 1024 * 1024; // 5MB

if (isset($_FILES['file'])) {
    $file = $_FILES['file'];
    
    $fileName = $file['name'];
    $fileTmpName = $file['tmp_name'];
    $fileSize = $file['size'];
    $fileError = $file['error'];
    
    $fileExt = strtolower(pathinfo($fileName, PATHINFO_EXTENSION));
    
    if (in_array($fileExt, $allowedFileTypes)) {
        if ($fileSize <= $maxFileSize) {
            // Upload file to server
            move_uploaded_file($fileTmpName, 'uploads/' . $fileName);
            echo 'File uploaded successfully';
        } else {
            echo 'File is too large. Maximum file size is 5MB';
        }
    } else {
        echo 'Invalid file type. Allowed file types are jpg, jpeg, png, gif';
    }
}

Keywords

file upload security vulnerabilities file validation file extension file size limit

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