Appointment Booking Calendar <= 1.3.96 - Missing Authorization to Arbitrary Booking Confirmation via 'cpabc_ipncheck' Parameter
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.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| WordPress plugin | Appointment Booking Calendar | <= 1.3.96 | 1.3.97 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N- Weakness (CWE)
CWE-862- Platform
- WordPress
- Package
Appointment Booking Calendar- Disclosed
- 21.11.2025
- Updated
- 11.10.2026 10:22
Sources and licenses
Wordfence Intelligence - 638217c4-7a37-49e4-8660-5510ace692ec - Wordfence Intelligence
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Copyright 2012-2026 Defiant Inc.
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Vulnerability history: Appointment Booking Calendar
All published vulnerabilities of this package (WordPress plugin), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 16
- First → latest
- 09.2015 06.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 3
- High 2
- Medium 11
Disclosures per year
- 2017: 0
- 2018: 0
- 2019: 1
- 2020: 2
- 2021: 0
- 2022: 1
- 2023: 0
- 2024: 1
- 2025: 4
- 2026: 2
earlier: 5
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Appointment Booking Calendar <= 1.3.96 - Missing Authorization to Arbitrary Booking Confirmation via 'cpabc_ipncheck' Parameter this entry
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