CVE-2026-11866: Unknown Appointment Booking Plugin

Medium severity, CVSS 5.4. EPSS: 0.1% chance of exploitation in the next 30 days.

The Appointment Booking Plugin WordPress plugin before 5.6.3 does not validate a CSRF nonce on several state-changing actions handled by its central request dispatcher, allowing attackers to perform privileged actions, such as overwriting the booking-form configuration or disconnecting the connected payment gateway, via Cross-Site Request Forgery against a logged-in administrator.

Affected products

• Unknown Appointment Booking Plugin: before 5.6.3 (fixed in 5.6.3)

Published 2026-07-16. Last modified 2026-07-16.