CVE-2026-16039

MStore API <= 4.20.0 - Insecure Direct Object Reference to Authenticated (Subscriber+) Order and Customer PII Disclosure

2026-08-03 00:00
Sai Praneeth Koti

Strategic Overview

Status
Patched in 4.21.0
Affected Plugin
MStore API – Create Native Android & iOS Apps On The Cloud
Affected Version
<= 4.20.0
CVSS
4.3Medium
Weakness type
CWE-639 · Authorization Bypass Through User-Controlled Key
CVE
CVE-2026-16039
View all MStore API – Create Native Android & iOS Apps On The Cloud vulnerabilities

At a glance

CVE-2026-16039 is a medium-severity Authorization Bypass Through User-Controlled Key vulnerability in the MStore API WordPress plugin, affecting versions <= 4.20.0. It carries a CVSS score of 4.3 (reachable over the network; low attack complexity). Exploitation requires an authenticated account at Subscriber level or above. The issue is fixed in version 4.21.0; sites on affected versions should update now. Disclosed August 2026, reported by Sai Praneeth Koti.

Vulnerability Overview

The MStore API plugin for WordPress is vulnerable to Insecure Direct Object Reference in versions up to, and including, 4.20.0. This is due to missing validation on a user controlled key. This makes it possible for authenticated attackers, with subscriber-level access and above, to perform an unauthorized action.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no interaction from a victim user.

CWE-639: Authorization Bypass Through User-Controlled Key

Reaching this weakness in MStore API <= 4.20.0 takes an account at Subscriber level or above. Authorization bypass through a user-controlled key, often called insecure direct object reference, means the application looks up a record by an identifier from the request without checking that the caller owns it.

Changing a number in the request is enough to read or modify other users' records, which on commerce and membership sites means customer data. For MStore API the fix is 4.21.0: builds <= 4.20.0 are affected, anything from 4.21.0 onward is not.

Remediation

Update to version 4.21.0, or a newer patched version

How does WordSec protect against this?

Because it turns on account access, WordSec's login security is the relevant layer: role-based two-factor, captcha and brute-force limits raise the cost of getting the account this needs. None of that substitutes for the fix: MStore API 4.21.0 closes this, and updating the plugin is the step that ends it.

  • Login Security
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2026-16039https://www.wordfence.com/threat-intel/vulnerabilities/id/348eb3f1-fa8e-42ae-b8a7-a1de3d196acfhttps://nvd.nist.gov/vuln/detail/CVE-2026-16039

Related records

Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C