Submeter #886961: macrozheng mall 1.0.3 Improper Validation of Specified Quantity in Input

A missing input validation vulnerability exists in the cart quantity update endpoint of mall version 1.0.3. The GET /cart/update/quantity endpoint allows authenticated users to set a negative integer value for the quantity parameter. The backend service (OmsCartItemServiceImpl.updateQuantity()) directly writes this value into the oms_cart_item table without any check for positivity. This negative quantity then propagates to order generation (oms_order_item.product_quantity) and payment processing, causing the system to compute negative totals and perform reverse stock adjustments. Specifically, during order creation, the lock_stock is decreased (since lock_stock += quantity with negative quantity), and upon simulated payment, the UPDATE pms_sku_stock SET stock = stock - quantity effectively increases the physical stock (because subtracting a negative adds to the value). This leads to inventory inflation, negative order amounts, and bypass of stock availability checks (the condition realStock < quantity always fails for negative numbers). An attacker can exploit this to artificially inflate stock, create orders with negative total amounts, and potentially trigger fraudulent refunds if integrated with a payment gateway. Proof of concept: after login, add a product to cart, update its quantity to -5, generate an order, and observe that the order total becomes negative and the stock increases after payment. This vulnerability is classified as CWE-20 (Improper Input Validation) and does not require race conditions or privilege escalation – a single authenticated request suffices. The maintainers have not responded to previous security reports; we are disclosing publicly.

• Fonte: ⚠️ https://github.com/macrozheng/mall/issues/984
• Utilizador: Anonymous User
• Submissão: 12/07/2026 09h02 (há 2 meses)
• Moderação: 25/08/2026 08h29 (1 month later)
• Estado: Aceite
• Entrada VulDB: 394944 [macrozheng mall até 1.0.3 /cart/update/quantity OmsCartItemServiceImpl.updateQuantity]
• Pontos: 20