# CVE-2026-82845: Masteriyo LMS PHP object injection in metadata deserialization

Source: https://junglewise.ai/threats/cve-2026-82845-masteriyo-lms-php-object-injection-in-metadata-deserialization  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-12. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-82845 · Severity: critical · CVSS 9.9 · Published 2026-09-12

Masteriyo LMS is a WordPress learning management system plugin used to deliver online courses. The plugin fails to safely validate data when retrieving user-stored metadata, allowing authenticated users (or unauthenticated in a weaker variant) to inject malicious PHP code that executes on the server. This leads to complete server compromise, with attackers able to run arbitrary commands, steal data, or deploy ransomware.

## Quick answers

**Is CVE-2026-82845 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-82845 being exploited in the wild.

**How severe is CVE-2026-82845?** Critical severity, with a CVSS score of 9.9, published 12 September 2026.

**Which products and versions are affected?** Masteriyo Masteriyo LMS before 3.4.1.

**Is there a fix for CVE-2026-82845?** A patch was published on 2026-09-12: Fixed in version 3.4.1 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-82845 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-82845?** Check whether anything you run is named in the advisory. 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.

## Technical details

The vulnerability is a PHP object injection (CWE-502) in metadata deserialization. User-supplied values stored as WordPress metadata are unsafely deserialized without validation, allowing an attacker to inject arbitrary PHP objects. Authenticated users with minimal account privileges can exploit this to achieve remote code execution via a gadget chain in a bundled library. An unauthenticated variant exists that yields arbitrary file write instead of code execution, requiring no authentication. The root cause is the absence of integrity checks and safe deserialization practices when reading metadata. The fix is available in version 3.4.1.

## Affected products

- Masteriyo Masteriyo LMS before 3.4.1

## Timeline

- 2026-09-10: disclosed
- 2026-09-12: advisory
- 2026-09-12: patched: Fixed in version 3.4.1

## References

- [https://wpscan.com/vulnerability/5ced30ea-8b78-495f-b10c-42b3f10adcb3/](https://wpscan.com/vulnerability/5ced30ea-8b78-495f-b10c-42b3f10adcb3/)