In a vulnerable application, the add-cart.php script simply takes the num (quantity) provided in the URL or POST body and adds it directly to the user's session or database cart without validation.
// 3. Inventory check if ($quantity > $product['stock']) $quantity = $product['stock']; $_SESSION['flash_message'] = "Reduced to available stock: $quantity";
: The num parameter is frequently used to designate the quantity or product ID . If not properly sanitized, it can be exploited via:
// Secure Code $quantity = intval($_GET['num']);
The script usually receives data via a GET or POST request. Let's assume the request looks like add-cart.php?id=123 .
?>
else $_SESSION['cart'][$product_id] = $quantity;
add-cart.php?num[$gt]=1000