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CVE-2026-8840

5.3 · MEDIUM

The Booking calendar, Appointment Booking System plugin for WordPress is vulnerable to authorization bypass in all versions up to, and including, 3.2.36.

Published Aug 15, 2026CWE-862EPSS 0.55%

Overview

CVE-2026-8840 is a medium-severity vulnerability. It was published on August 15, 2026 and has a CVSS 3.1 base score of 5.3 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 5.3, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical description

The Booking calendar, Appointment Booking System plugin for WordPress is vulnerable to authorization bypass in all versions up to, and including, 3.2.36. This is due to the plugin not properly verifying that a user is authorized to perform an action. This makes it possible for unauthenticated attackers to mark arbitrary reservations as paid or completed, cancel legitimate payments, auto-approve reservations, and trigger transactional booking emails by writing attacker-supplied payment status and transaction data directly into the payments table. The auto-approval of reservations is only triggered when the 'enable_psuccess_approval' site option is enabled, but payment status manipulation and email dispatch are exploitable regardless of that setting.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

Refplugins.trac.wordpress.org/browser/booking-calendar/tags/3.2.35/admin/controllers/Payment.php#L16Refplugins.trac.wordpress.org/browser/booking-calendar/tags/3.2.35/admin/controllers/Payment.php#L26Refplugins.trac.wordpress.org/browser/booking-calendar/tags/3.2.35/booking_calendar.php#L131Refplugins.trac.wordpress.org/browser/booking-calendar/tags/3.2.35/booking_calendar.php#L578Refplugins.trac.wordpress.org/browser/booking-calendar/tags/3.2.36/admin/controllers/Payment.php#L16Refplugins.trac.wordpress.org/browser/booking-calendar/tags/3.2.36/admin/controllers/Payment.php#L26Refplugins.trac.wordpress.org/browser/booking-calendar/tags/3.2.36/booking_calendar.php#L131Refplugins.trac.wordpress.org/browser/booking-calendar/tags/3.2.36/booking_calendar.php#L578Refwww.wordfence.com/threat-intel/vulnerabilities/id/88409bb0-5cb0-4f63-b8f0-d72f54fa17b0?source=cve

How CyberStrike helps

Frequently asked questions

What is CVE-2026-8840?

CVE-2026-8840 is a medium-severity vulnerability. It was published on August 15, 2026 and has a CVSS 3.1 base score of 5.3 (MEDIUM).

How severe is CVE-2026-8840?

This vulnerability has a CVSS 3.1 base score of 5.3, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2026-8840?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2026-8840?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-8840 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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