# CVE-2026-118090: MasterStudy LMS PHP object injection in subscriber handling

Source: https://junglewise.ai/threats/cve-2026-118090-subscriber-php-object-injection-in-masterstudy-lms-3-7-55  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-30. Updated: 2026-10-30  
License: CC BY 4.0 with a link back

CVE-2026-118090 · Severity: high · CVSS 8.8 · Published 2026-10-30

MasterStudy LMS is a WordPress plugin for creating online learning management systems. A PHP object injection vulnerability in versions 3.7.55 and earlier allows authenticated subscribers to execute arbitrary code on the hosting server, potentially leading to complete site compromise and data theft.

Technologies: [StylemixThemes MasterStudy LMS](https://junglewise.ai/threats/technologies/masterstudy-lms). Vendors: [StylemixThemes](https://junglewise.ai/threats/vendors/stylemixthemes).

## Quick answers

**Is CVE-2026-118090 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-118090 being exploited in the wild.

**How severe is CVE-2026-118090?** High severity, with a CVSS score of 8.8, published 30 October 2026.

**Which products and versions are affected?** StylemixThemes MasterStudy LMS 3.7.55 and earlier.

**Is there a fix for CVE-2026-118090?** Yes: fixed in 3.7.56. Until then: As an immediate action, update the affected plugin to version 3.7.56 or later. Patchstack has issued a mitigation rule to block exploitation attempts until the update is applied. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-118090 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-118090?** Check whether you run StylemixThemes MasterStudy LMS at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 3.7.56

As an immediate action, update the affected plugin to version 3.7.56 or later. Patchstack has issued a mitigation rule to block exploitation attempts until the update is applied.

## Technical details

The plugin contains a PHP object injection flaw in its subscriber-related functionality that allows authenticated users with subscriber privileges to manipulate object serialization and trigger arbitrary code execution on the server. This is an injection vulnerability (OWASP A3) requiring only subscriber-level authentication—a low privilege requirement that is easy to obtain on most WordPress installations.

## Affected products

- StylemixThemes MasterStudy LMS 3.7.55 and earlier

## Timeline

- 2026-10-30: disclosed
- 2026-10-30: advisory: Patchstack advisory published

## References

- [https://wordpress.org/plugins](https://wordpress.org/plugins)
- [https://patchstack.com/database/wordpress/plugin/masterstudy-lms-learning-management-system/vulnerability/wordpress-masterstudy-lms-plugin-3-7-55-php-object-injection-vulnerability?_s_id=cve](https://patchstack.com/database/wordpress/plugin/masterstudy-lms-learning-management-system/vulnerability/wordpress-masterstudy-lms-plugin-3-7-55-php-object-injection-vulnerability?_s_id=cve)

## Related threats

- [StylemixThemes MasterStudy LMS content injection via XSS](https://junglewise.ai/threats/cve-2026-119478-improper-neutralization-of-script-related-html-tags-in-a-web)
- [MasterStudy LMS path traversal in file import](https://junglewise.ai/threats/cve-2026-80067-masterstudy-lms-plugin-for-wordpress-before-3-7-50-contains-a)
- [StylemixThemes MasterStudy LMS broken access control](https://junglewise.ai/threats/cve-2026-118092-missing-authorization-vulnerability-in-stylemixthemes)
- [MasterStudy LMS unauthenticated arbitrary file deletion](https://junglewise.ai/threats/cve-2026-78284-masterstudy-lms-unauthenticated-arbitrary-file-deletion)
- [StylemixThemes MasterStudy LMS user state manipulation](https://junglewise.ai/threats/cve-2026-28145-stylemixthemes-masterstudy-lms-user-state-manipulation)