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Missing AuthorizationWeakness · CWE-862

CVE-2025-13317

MEDIUM · 5.3 CVSS v3.1 Published 2025-11-22
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 Appointment Booking Calendar plugin for WordPress is vulnerable to Missing Authorization in all versions up to, and including, 1.3.96. This is due to the plugin exposing an unauthenticated booking processing endpoint (cpabc_appointments_check_IPN_verification) that trusts attacker-supplied payment notifications without verifying their origin, authenticity, or requiring proper authorization checks. This makes it possible for unauthenticated attackers to arbitrarily confirm bookings and insert them into the live calendar via the 'cpabc_ipncheck' parameter, triggering administrative and customer notification emails and disrupting operations.

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 Appointment Booking Calendar plugin for WordPress versions up to 1.3.96 lack authorization checks on the cpabc_appointments_check_IPN_verification endpoint. This allows unauthenticated attackers to submit arbitrary booking confirmations via the cpabc_ipncheck parameter, injecting fake bookings into the calendar and triggering notification emails to admins and customers.

MitigationUpdate to version 1.3.97 or later which includes proper authorization validation. Alternatively, temporarily disable the plugin or restrict access to the vulnerable endpoint at the web server/firewall level until patching is feasible.

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 plugin installation and version
    In WordPress admin, go to Plugins > Installed Plugins and locate 'Appointment Booking Calendar'. Note the version number displayed under the plugin name.
    Affected if The plugin is installed and the version listed is 1.3.96 or lower.
  2. Compare version to affected range
    Review the version number identified in step 1. The vulnerability affects all versions up to and including 1.3.96.
    Affected if The installed version is 1.3.96 or any earlier version number.
  3. Identify the vulnerable endpoint
    Locate the file handling the cpabc_appointments_check_IPN_verification request. This is typically in the plugin directory, often in files named ipn.php, ipnhandler.php, or similar files containing the IPN verification logic.
    Affected if The plugin file containing 'cpabc_appointments_check_IPN_verification' or 'cpabc_ipncheck' exists in the installation.
  4. Test endpoint accessibility
    Send a crafted request to the suspected endpoint (commonly at /?cpabc_ipncheck=1 or similar URL pattern used by the plugin's IPN handler) without providing any authentication credentials.
    Affected if The endpoint returns a successful response or processes the request without requiring authentication or validation.
  5. Audit recent bookings for suspicious activity
    In WordPress admin, navigate to the plugin's booking management section and review recent appointment submissions. Look for bookings with unusual timestamps, invalid customer data, or unexpected notification triggers.
    Affected if There are bookings in the system that were not created through the normal admin or customer-facing booking process, or notification emails were sent without valid bookings.

A user is affected if the Appointment Booking Calendar plugin version is 1.3.96 or lower and the cpabc_appointments_check_IPN_verification endpoint is accessible without authentication.

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

Update to version 1.3.97 or later which includes proper authorization validation. Alternatively, temporarily disable the plugin or restrict access to the vulnerable endpoint at the web server/firewall level until patching is feasible.

Recommended fix Moderate confidence

Version 1.3.97 or later

  1. Update the Appointment Booking Calendar plugin to the latest available version from the WordPress plugin repository
  2. After updating, verify that the cpabc_appointments_check_IPN_verification endpoint now properly validates payment notifications
  3. Confirm that unauthorized bookings can no longer be confirmed via the cpabc_ipncheck parameter
  4. Test that legitimate booking workflows still function correctly including admin and customer notifications

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

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
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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-2025-13317 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