CVE-2026-100193: Tutor LMS <= 4.1.0 - Reflected Cross-Site Scripting via 'tab' Parameter
The Tutor LMS – eLearning and online course solution plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the 'tab' parameter in all versions up to, and including, 4.1.0 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link. Exploitation requires the targeted lesson page to have an empty nav-items array — a condition that occurs naturally when a lesson has no post content, no attachments, and comments are disabled or the viewer is not logged in — which bypasses the inarray() tab validation and allows the raw attacker-controlled value to reach the sink.
Affected Software
Event History
Frequently Asked Questions
Which lesson pages are exposed to this issue?
Exploitation requires a lesson whose nav-items array is empty. This occurs naturally when the lesson has no post content or attachments and comments are disabled, or when the viewer is not logged in.
What does an attacker need to exploit it?
An attacker does not need to authenticate, but must persuade a user to perform an action such as clicking a crafted link. The crafted request must target a lesson page meeting the empty nav-items condition.
How can I determine whether a lesson is likely affected?
Review lessons for the required condition: no post content, no attachments, and comments disabled; unauthenticated viewing can also produce the condition described. Pages meeting that condition may allow an attacker-controlled tab parameter to bypass validation.