What are some potential pitfalls of not properly restricting user language settings in PHP scripts?

If user language settings are not properly restricted in PHP scripts, it can lead to security vulnerabilities such as SQL injection attacks or cross-site scripting (XSS) attacks. To solve this issue, you should always sanitize and validate user input to prevent malicious code from being executed.

// Restricting user language settings in PHP scripts
$userLanguage = isset($_POST['language']) ? $_POST['language'] : 'default_language';

// Validating user input
$allowedLanguages = ['en', 'es', 'fr']; // List of allowed languages
if (!in_array($userLanguage, $allowedLanguages)) {
    $userLanguage = 'default_language'; // Set default language if input is not allowed
}