# CVE-2026-5167: Masteriyo LMS <= 2.1.7 - Unauthenticated Authorization Bypass to Arbitrary Order Completion via Stripe Webhook Endpoint

> Unauthenticated attackers can bypass Stripe webhook verification to mark orders as paid, gaining unauthorized access to premium course content.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 8 Apr 2026
- **Updated:** 8 Apr 2026
- **Also known as:** GHSA-v3v2-w9v8-q7h6

## What is CVE-2026-5167?

CVE-2026-5167 is a medium-severity authentication bypass vulnerability in Masteriyo LMS – Online Course Builder for eLearning, LMS & Education, published on 8 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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.

Weakness: CWE-639 (Authorization Bypass Through User-Controlled Key)

## Which versions are affected by CVE-2026-5167?


## How do I fix CVE-2026-5167?

No fix has been published for CVE-2026-5167 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-5167 being exploited?

There is no known exploitation of CVE-2026-5167 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-5167 and fix it if it is affected.

What it is: CVE-2026-5167 is a medium-severity authentication bypass vulnerability in Masteriyo LMS – Online Course Builder for eLearning, LMS & Education, published on 8 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-5167 in the wild and no public exploit code.

Affected product: Masteriyo LMS – Online Course Builder for eLearning, LMS & Education. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-5167/ (Markdown: https://insights.sbomify.com/CVE-2026-5167/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-5167
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-5167
- OSV: https://osv.dev/vulnerability/CVE-2026-5167

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-5167/
Summaries are generated and may contain mistakes; the official description above is the record.