Masteriyo LMS <= 2.1.7 - Unauthenticated Authorization Bypass to Arbitrary Order Completion via Stripe Webhook Endpoint

Summary

The Masteriyo LMS – Online Course Builder for eLearning, LMS & Education plugin for WordPress is vulnerable to Authorization Bypass Through User-Controlled Key in versions up to and including 2.1.7. This is due to insufficient webhook signature verification in the handle_webhook() function. The webhook endpoint processes unauthenticated requests and only performs signature verification if both the webhook_secret setting is configured AND the HTTP_STRIPE_SIGNATURE header is present. Since webhook_secret defaults to an empty string, the webhook processes attacker-controlled JSON payloads without any verification. This makes it possible for unauthenticated attackers to send fake Stripe webhook events with arbitrary order_id values in the metadata, mark any order as completed without payment, and gain unauthorized access to paid course content.

Timeline

1. Apr 8, 2026, 6:43 AM UTCCVE published
2. Apr 8, 2026, 2:48 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: yes · Technical impact: partial

3. Apr 8, 2026, 5:17 PM UTCRecord last updated

Affected versions

• masteriyo Masteriyo LMS – Online Course Builder for eLearning, LMS & Education

  through 2.1.7

References 6