CVE-2025-59577: MasterStudy LMS Race Condition Vulnerability

CVE-2025-59577 Overview

CVE-2025-59577 is a race condition vulnerability in the Stylemix MasterStudy LMS plugin for WordPress. The flaw affects masterstudy-lms-learning-management-system versions up to and including 3.6.20. Authenticated attackers with low-level privileges can exploit concurrent execution of shared resources to manipulate integrity of plugin data. The issue is tracked under CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization).

Critical Impact
An authenticated attacker can leverage improper synchronization in the MasterStudy LMS plugin to bypass business logic controls and modify learning management data through concurrent requests.

Affected Products

Stylemix MasterStudy LMS plugin for WordPress
All versions from initial release through 3.6.20
WordPress sites running the masterstudy-lms-learning-management-system plugin

Discovery Timeline

2025-09-22 - CVE-2025-59577 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-59577

Vulnerability Analysis

The vulnerability stems from the plugin's failure to enforce proper synchronization when multiple requests operate on shared resources. MasterStudy LMS handles operations such as course enrollment, quiz submissions, and progress tracking through endpoints that assume serial execution. Concurrent requests targeting the same resource can interleave in ways the developers did not anticipate.

Race conditions of this class typically allow attackers to bypass one-time checks. For example, an attacker may submit multiple parallel requests that all pass a validation step before any of them commit state changes. The result is duplicated actions, bypassed limits, or corrupted records.

The attack requires authentication with low privileges, which is trivial to obtain on LMS platforms that accept student registrations. The impact is limited to integrity of plugin data, with no direct confidentiality or availability consequences reported.

Root Cause

The root cause is missing locking or atomicity guarantees around state-modifying operations in the plugin. When two requests read a shared value, compute an update, and write back the result without synchronization, the second write can overwrite the first without accounting for it. This is a classic time-of-check to time-of-use (TOCTOU) pattern within a PHP/MySQL execution context.

Attack Vector

The attack vector is network-based and requires an authenticated account on the target WordPress site. An attacker sends multiple simultaneous HTTP requests to a vulnerable plugin endpoint. The requests must arrive within a window narrow enough that they execute in parallel across PHP-FPM workers before the first request finalizes its database write.

Refer to the Patchstack Vulnerability Report for additional technical context on the affected endpoints.

Detection Methods for CVE-2025-59577

Indicators of Compromise

Multiple identical or near-identical requests to MasterStudy LMS endpoints arriving within milliseconds from the same authenticated session
Unexpected duplication of course enrollments, quiz attempts, or coupon redemptions in plugin data tables
Database rows with identical timestamps for actions that should be unique per user

Detection Strategies

Enable WordPress plugin version monitoring to identify sites running masterstudy-lms-learning-management-system at version 3.6.20 or earlier
Inspect web server access logs for burst patterns targeting /wp-admin/admin-ajax.php or REST endpoints exposed by the plugin
Compare application-layer state (enrollments, purchases, submissions) against expected counts per authenticated user

Monitoring Recommendations

Alert on more than N concurrent requests from a single session ID to the same plugin endpoint within a one-second window
Track integrity of LMS records by scheduling consistency checks on enrollment and payment tables
Retain HTTP request logs with millisecond-precision timestamps to reconstruct race attempts

How to Mitigate CVE-2025-59577

Immediate Actions Required

Inventory all WordPress installations and identify sites running MasterStudy LMS at or below version 3.6.20
Update the plugin to a version released after 3.6.20 that contains the vendor's fix
Restrict registration on public-facing LMS sites if a patch cannot be applied immediately, since exploitation requires an authenticated account

Patch Information

Stylemix has addressed the issue in a version released after 3.6.20. Administrators should consult the Patchstack Vulnerability Report for the exact fixed version and apply the update through the WordPress plugin manager.

Workarounds

Deploy a web application firewall rule that rate-limits requests to MasterStudy LMS endpoints per authenticated session
Enforce single-request-in-flight semantics at the reverse proxy for state-changing plugin actions
Temporarily disable the plugin on sites where the affected functionality is not business-critical until a patched version is installed

bash

# Example nginx rate limit for authenticated LMS endpoints
limit_req_zone $cookie_wordpress_logged_in zone=lms_zone:10m rate=2r/s;

location ~ ^/wp-admin/admin-ajax\.php$ {
    limit_req zone=lms_zone burst=3 nodelay;
    proxy_pass http://php_backend;
}