What potential issues or pitfalls should be considered when using PHP to handle form submissions with dropdown menus?

One potential issue when using PHP to handle form submissions with dropdown menus is that the selected value may not be properly sanitized, leading to security vulnerabilities such as SQL injection. To prevent this, always sanitize user input before using it in queries or other operations.

// Sanitize the selected dropdown value before using it
$selected_option = filter_input(INPUT_POST, 'dropdown_menu', FILTER_SANITIZE_STRING);