Are there any potential pitfalls in using variables to track user navigation in PHP?

One potential pitfall in using variables to track user navigation in PHP is the risk of data manipulation or injection by malicious users. To prevent this, it is important to sanitize and validate user input before storing it in variables. Additionally, using session variables or cookies to track user navigation can provide a more secure and reliable way to store user data.

// Sanitize and validate user input before storing in variables
$user_input = $_POST['user_input'];
$sanitized_input = filter_var($user_input, FILTER_SANITIZE_STRING);

// Using session variables to track user navigation
session_start();
$_SESSION['navigation_history'][] = $sanitized_input;