What are the potential security risks associated with allowing users to navigate back to a form submission page in PHP?

Allowing users to navigate back to a form submission page in PHP can pose security risks such as resubmitting the form data multiple times or exposing sensitive information in the URL. To prevent these risks, you can implement a post-redirect-get pattern where after the form is submitted, the user is redirected to a different page to avoid resubmission.

// Check if the form has been submitted
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    // Process form data
    // Redirect to a different page to avoid resubmission
    header("Location: success.php");
    exit();
}