WordPress security changelog
CRITICAL CVE-2026-82845 Received

Masteriyo LMS permits low-privilege object injection and code execution

Masteriyo LMS before 3.4.1 deserializes attacker-controlled metadata when it is read back. A minimally privileged account can inject a PHP object and use a class bundled with the plugin to write and execute arbitrary server-side code; an unauthenticated variant provides arbitrary file write. The authoritative export does not identify the metadata key, write endpoint, or triggering read path.

CVE / CNA score 9.9 CVSS 3.1 · 134c704f-9b21-4f2e-91b3-4a467353bcc0
NVD score Pending NVD has not published its own CVSS assessment.
Component
Masteriyo LMS
Plugin slug
masteriyo-lms
Affected
< 3.4.1
Safe version
3.4.1
Published
Sep 12, 2026
Weakness
CWE-502 — Deserialization of Untrusted Data

This CVE was published Sep 12, 2026 and is one of 7 known issues for this plugin.

What to do

Update, patch or deactivate.

Update Masteriyo LMS to 3.4.1 or later. The authoritative affected range ends before 3.4.1. The application-level fix must keep untrusted metadata out of PHP deserialization and prevent user-controlled file paths or content from reaching file-write operations.

A safe version is available, so updating to that version or later is the preferred remediation. If an immediate update is not practical, consider a targeted application patch or temporarily restricting the affected functionality.

Deactivate only when warranted by your risk profile, or when advised by your hosting provider in the limited circumstances where the vulnerability cannot otherwise be mitigated. If you’re unsure which action is appropriate, contact Fused or your hosting provider for guidance.

Source record

Technical description

The Masteriyo LMS WordPress plugin before 3.4.1 does not prevent user-supplied values held as metadata from being deserialized when they are read back, allowing users with a minimal account to inject arbitrary PHP objects and, by way of a class shipped in a library bundled with the Masteriyo LMS WordPress plugin before 3.4.1, write and execute arbitrary code on the server. A weaker form of the same issue is reachable without an account and yields an arbitrary file write rather than code execution.

CVE / CNA vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

References

Primary and upstream sources