CVE-2026-81338

MasterStudy LMS <= 3.7.49 - Authenticated (Subscriber+) HTML Injection

2026-09-21 00:00
Jaime F. Murillo

Strategic Overview

Status
Patched in 3.7.50
Affected Plugin
MasterStudy LMS WordPress Plugin – for Online Courses and Education
Affected Version
<= 3.7.49
CVSS
6.3Medium
Weakness type
CWE-20 · Improper Input Validation
CVE
CVE-2026-81338
View all MasterStudy LMS WordPress Plugin – for Online Courses and Education vulnerabilities

At a glance

CVE-2026-81338 is a medium-severity Improper Input Validation vulnerability in the MasterStudy LMS WordPress Plugin WordPress plugin, affecting versions <= 3.7.49. It carries a CVSS score of 6.3 (reachable over the network; low attack complexity). Exploitation requires an authenticated account at Subscriber level or above. The issue is fixed in version 3.7.50; sites on affected versions should update now. Disclosed September 2026, reported by Jaime F. Murillo.

Vulnerability Overview

The MasterStudy LMS WordPress Plugin – for Online Courses and Education plugin for WordPress is vulnerable to HTML Injection in all versions up to, and including, 3.7.49. This makes it possible for authenticated attackers, with Subscriber-level access and above, to inject HTML in course discussions.

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-20: Improper Input Validation

Reaching this weakness in MasterStudy LMS WordPress Plugin <= 3.7.49 takes an account at Subscriber level or above. Improper input validation means the application accepts input without confirming it has the form, type or range the code downstream assumes.

The concrete impact depends on where the unvalidated value lands, which is why records in this class range from cosmetic bugs to full compromise. For MasterStudy LMS WordPress Plugin the fix is 3.7.50: builds <= 3.7.49 are affected, anything from 3.7.50 onward is not.

Remediation

Update to version 3.7.50, or a newer patched version

How does WordSec protect against this?

An attacker needs Subscriber access first, so the firewall sees the attempt as traffic from a logged-in account: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: MasterStudy LMS WordPress Plugin 3.7.50 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2026-81338https://www.wordfence.com/threat-intel/vulnerabilities/id/cfde2cf5-d40a-4843-946a-5555b4d95ecfhttps://nvd.nist.gov/vuln/detail/CVE-2026-81338

Related records

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