CVE-2026-79406: macrozheng mall Business Logic Vulnerability

CVE-2026-79406 Overview

CVE-2026-79406 is a business logic vulnerability in the macrozheng mall e-commerce platform through version 1.0.3. The flaw resides in the OmsCartItemServiceImpl.updateQuantity function reachable via the /cart/update/quantity endpoint. Manipulation of the quantity argument triggers business logic errors [CWE-840] that authenticated remote attackers can abuse to alter cart state in unintended ways. The vendor removed the associated GitHub issue without explanation, and no official patch has been published at the time of this writing.

Critical Impact
Authenticated remote attackers can manipulate the quantity parameter in cart update requests to bypass intended business rules in the macrozheng mall shopping platform.

Affected Products

macrozheng mall versions up to and including 1.0.3
Deployments exposing the /cart/update/quantity endpoint
Applications embedding the vulnerable OmsCartItemServiceImpl service class

Discovery Timeline

2026-08-25 - CVE-2026-79406 published to NVD
2026-08-27 - Last updated in NVD database

Technical Details for CVE-2026-79406

Vulnerability Analysis

The vulnerability is a business logic error [CWE-840] in the cart quantity update flow of the macrozheng mall Java-based e-commerce project. The updateQuantity method in OmsCartItemServiceImpl accepts a client-supplied quantity value and updates the corresponding cart item without enforcing complete server-side constraints on the value.

Because the endpoint requires low-privileged authentication and no user interaction, any registered shopper can submit crafted requests. The impact is limited to integrity of application data, specifically cart state. Confidentiality and availability are not directly affected.

The vendor deleted GitHub issue #984 tracking this report without public explanation, and no CVE-mapped fix commit is currently referenced by the advisory sources.

Root Cause

The root cause is insufficient enforcement of business rules on the quantity parameter accepted by the /cart/update/quantity handler. The service layer trusts the client-supplied value and updates the persistent cart record without validating that the value satisfies domain constraints such as positivity, upper bounds, stock availability, or per-user purchase limits.

Attack Vector

An authenticated attacker sends an HTTP request to /cart/update/quantity with a manipulated quantity field targeting a cart item they own. Because the flaw is a logic error rather than a memory-safety or injection issue, exploitation does not require malformed payloads. The attacker uses legitimate request syntax with out-of-policy values, and the server persists the resulting inconsistent state.

For technical details, refer to the VulDB entry for CVE-2026-79406 and the macrozheng mall repository.

Detection Methods for CVE-2026-79406

Indicators of Compromise

Repeated POST or PUT requests to /cart/update/quantity from a single authenticated session within a short interval.
Cart records containing quantity values that violate application policy, such as negative, zero, or unusually large integers.
Order or checkout records referencing cart items whose historical quantity values were modified outside the standard UI flow.

Detection Strategies

Instrument the OmsCartItemServiceImpl.updateQuantity method to log the caller identity, item ID, prior quantity, and new quantity for every invocation.
Add a web application firewall (WAF) rule that inspects requests to /cart/update/quantity and flags values outside a defined numeric range.
Correlate application logs with order fulfillment events to identify cart mutations that immediately precede checkout at anomalous totals.

Monitoring Recommendations

Alert on any HTTP 200 response to /cart/update/quantity where the request body contains non-positive integers or values exceeding stock thresholds.
Track per-user rate of cart update calls and flag sessions exceeding a baseline established from normal shopper behavior.
Review database audit trails on the cart item table for updates that bypass expected constraints.

How to Mitigate CVE-2026-79406

Immediate Actions Required

Restrict access to the /cart/update/quantity endpoint at the reverse proxy or API gateway until a validated fix is in place.
Apply server-side validation ensuring quantity is a positive integer within a defined upper bound before invoking updateQuantity.
Enforce inventory and per-user purchase limits at the service layer rather than only in the client UI.
Audit existing cart and order records for anomalous quantities and reconcile any discrepancies.

Patch Information

No vendor patch is currently referenced in the NVD entry. The vendor removed the associated GitHub issue #984 without providing remediation guidance. Operators of macrozheng mall should monitor the macrozheng mall repository for future commits addressing the OmsCartItemServiceImpl.updateQuantity logic and apply local hardening in the interim.

Workarounds

Implement a request filter or Spring interceptor that rejects /cart/update/quantity calls whose quantity value falls outside allowed bounds.
Add database-level CHECK constraints on the cart item table to prevent persistence of invalid quantity values.
Require re-validation of stock availability and pricing at checkout so that manipulated cart quantities cannot translate into fulfilled orders.

bash

# Example nginx rule to block obviously invalid quantity values
location /cart/update/quantity {
    if ($request_method !~ ^(POST|PUT)$) { return 405; }
    if ($arg_quantity ~ "^-|^0$|^[0-9]{4,}$") { return 400; }
    proxy_pass http://mall-backend;
}