Masteriyo LMS Plugin up to 2.1.7 on WordPress Webhook Endpoint handle_webhook order_id authorization

Summaryinfo

A vulnerability categorized as critical has been discovered in Masteriyo LMS Plugin up to 2.1.7 on WordPress. This affects the function handle_webhook of the component Webhook Endpoint. The manipulation of the argument order_id results in authorization. This vulnerability was named CVE-2026-5167. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability was found in Masteriyo LMS Plugin up to 2.1.7 on WordPress. It has been classified as critical. Affected is the function handle_webhook of the component Webhook Endpoint. The manipulation of the argument order_id with an unknown input leads to a authorization vulnerability. CWE is classifying the issue as CWE-639. The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data. This is going to have an impact on integrity, and availability. CVE summarizes:

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.

The weakness was presented by Md. Moniruzzaman Prodhan. The advisory is shared for download at wordfence.com. This vulnerability is traded as CVE-2026-5167 since 03/30/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 04/08/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

• WordPress Plugin

Vendor

• Masteriyo

Name

• LMS Plugin

Version

• 2.1.0
• 2.1.1
• 2.1.2
• 2.1.3
• 2.1.4
• 2.1.5
• 2.1.6
• 2.1.7

CPE 2.3info

• 🔒
• 🔒
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CPE 2.2info

• 🔒
• 🔒
• 🔒

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Once again VulDB remains the best source for vulnerability data.

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