CVE-2026-106676 in Mall Server
Summary
by MITRE • 10/26/2026
qiujie mall-server 0.0.1-SNAPSHOT contains an integer overflow in CartServiceImpl that allows an authenticated user to wrap a cart quantity to a negative value. The order creation flow does not validate the resulting quantity and passes it to the stock update query, increasing inventory and creating negative-value orders.
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Analysis
by VulDB Data Team • 10/26/2026
The vulnerability identified within qiujie mall-server version 0.0.1-SNAPSHOT represents a critical logic flaw rooted in improper handling of integer arithmetic during e-commerce transaction processing. Specifically, the CartServiceImpl component fails to enforce strict bounds checking on cart item quantities before performing addition or subtraction operations. This lack of validation allows an authenticated user to manipulate the quantity field such that it wraps around due to integer overflow characteristics inherent in fixed-width data types used by the underlying programming language runtime. When a user reduces their cart quantity beyond zero, instead of being capped at zero or triggering an error, the value underflows into negative territory. This behavior is not merely a cosmetic issue but fundamentally breaks the assumption that product quantities must be non-negative integers throughout the order lifecycle.
From a technical perspective, this flaw aligns with CWE-190 Integer Overflow or Wraparound and CWE-20 Improper Input Validation. The application logic assumes that any value passed to subsequent services is valid within business constraints. However, because the CartServiceImpl does not sanitize input before passing it downstream, the negative quantity propagates through the order creation flow without interception. This architectural oversight allows malicious actors to exploit the gap between user-facing interface validation and backend service-level enforcement. The absence of defensive programming practices at this layer means that internal data integrity is compromised by external inputs that appear syntactically valid but are semantically invalid for business operations.
The operational impact of this vulnerability extends beyond simple inventory discrepancies; it enables financial fraud through the creation of negative-value orders. When an order containing a negatively quantified item is processed, the system interprets this as a return or credit event rather than a sale. Consequently, the stock update query increases the available inventory count instead of decreasing it. This results in phantom stock that does not correspond to physical goods, allowing attackers to artificially inflate warehouse levels. Furthermore, because the order value calculation typically involves multiplying quantity by unit price, a negative quantity yields a negative total price. Depending on how the payment gateway and accounting systems handle these transactions, this can lead to erroneous refunds, credit balance manipulation, or complete bypass of payment requirements if the system treats zero or negative totals as free orders.
This exploitation path maps directly to MITRE ATT&CK techniques related to Resource Manipulation and Financial Fraud. An attacker with valid authentication credentials can systematically exploit this flaw to gain unauthorized inventory credits or generate fraudulent transactions that drain financial resources through automated refund processing systems. The severity is heightened by the fact that it requires only standard user privileges, making widespread exploitation feasible without advanced privilege escalation steps.
Mitigation strategies must focus on implementing robust input validation at multiple layers of the application stack. First, CartServiceImpl should enforce strict positive integer constraints for all quantity fields before any arithmetic operations are performed. This includes validating both incoming requests and intermediate calculation results to ensure they remain within expected business ranges. Second, database-level constraints such as CHECK constraints or NOT NULL with minimum value limits on inventory tables can provide a final safety net against invalid state changes. Additionally, implementing idempotency checks and transactional integrity controls ensures that partial failures do not leave the system in an inconsistent state where stock levels are out of sync with order records. Regular security code reviews focusing on arithmetic operations involving user-controlled data are essential to prevent similar integer overflow vulnerabilities from recurring in other modules of the platform.