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Authorization Bypass (IDOR)Weakness · CWE-639

CVE-2026-5167

MEDIUM · 5.3 CVSS v3.1 Published 2026-04-08
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
62/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The Masteriyo LMS WordPress plugin has an authorization bypass vulnerability in its Stripe webhook handler. The handle_webhook() function only performs signature verification when BOTH a webhook_secret is configured AND the HTTP_STRIPE_SIGNATURE header is present. Since webhook_secret defaults to empty, unauthenticated attackers can send arbitrary JSON payloads to mark orders as completed without payment and access paid course content.

MitigationConfigure a non-empty webhook_secret in the plugin settings and ensure signature verification occurs for all webhook requests, regardless of whether a secret is configured.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Confirm Masteriyo LMS plugin installation
    Check the WordPress plugins directory or wp-content/plugins folder for the masteriyo directory, or query the wp_plugins database table for an entry named 'masteriyo' or 'LMS' by Masteriyo
    Affected if The plugin is not installed - no action needed; if installed, continue to next checks
  2. Identify the plugin version
    Read the main plugin file (usually masteriyo.php or index.php in the masteriyo plugin folder) and locate the version definition, or query the wp_options table for the option_name containing 'masteriyo_version'
    Affected if Unable to determine version - treat as potentially affected and proceed with configuration checks
  3. Examine Stripe webhook configuration
    Navigate to the plugin settings in WordPress admin under Masteriyo settings, look for Stripe or payment settings, and check if webhook_secret is configured (not empty)
    Affected if webhook_secret field is empty or not set - the vulnerability is present because signature verification is bypassed by default
  4. Verify webhook endpoint accessibility
    Access the webhook endpoint URL (typically /?rest_route=/masteriyo/v1/stripe/webhook or similar under the WordPress site URL) and check if it responds, or check the plugin source code for webhook handler registration
    Affected if The webhook endpoint is publicly accessible and responds to requests - combined with empty webhook_secret, the flaw is exploitable

A user is affected if the Masteriyo LMS plugin is installed with an empty or unconfigured webhook_secret in the Stripe settings, allowing unauthenticated webhook requests to be processed and potentially grant unauthorized access to premium content.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Configure a non-empty webhook_secret in the plugin settings and ensure signature verification occurs for all webhook requests, regardless of whether a secret is configured.

Recommended fix Moderate confidence

Version 2.1.8 or later

  1. 1. Navigate to the WordPress admin dashboard
  2. 2. Go to Plugins > Installed Plugins
  3. 3. Find Masteriyo LMS plugin
  4. 4. Check if an update is available (version 2.1.8 or later)
  5. 5. If update available, click 'Update Now' to upgrade to the patched version
  6. 6. After upgrading, navigate to Masteriyo LMS settings > Webhooks
  7. 7. Verify that a strong, non-empty webhook_secret is configured
  8. 8. Confirm the Stripe webhook endpoint is using the updated version

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-5167 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data