CVE-2026-82850

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 plugin, 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.

The Masteriyo LMS WordPress plugin before 3.4.2 does not verify that the user making the request owns the course-progress records being returned, allowing any authenticated user, such as a self-registered subscriber, to read another user's learning activity. The ownership check it applies is skipped whenever the requested account is not named with a non-zero value, in which case the records of every learner on the site are returned at once.

The Masteriyo LMS WordPress plugin before 3.4.1 does not verify ownership of, or restrict the type of, the records a user requests for download, allowing users with the instructor role to retrieve the full content and metadata of arbitrary posts, including other instructors' private and draft courses.

The Masteriyo LMS WordPress plugin before 3.4.1 does not sanitise and escape one of its course fields before outputting it back in the course editor, allowing users with the instructor role to perform Stored Cross-Site Scripting attacks against higher privileged users such as administrators.

The Masteriyo LMS WordPress plugin before version 3.4.0 does not sanitise and escape some course settings before outputting them in a page available to all visitors, allowing users with a course-author role to perform Stored Cross-Site Scripting attacks that run in the session of anyone viewing the course, including a logged-in administrator.

The Masteriyo LMS WordPress plugin before 2.2.1 does not perform authorization checks in a course-progress REST API controller, allowing unauthenticated users to read and permanently delete any user's course-progress records.