CVE-2026-11866

What is known

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.

Business impact

Successful exploitation of CVE-2026-11866, a medium vulnerability (CVSS 5.4) affecting the affected product, may affect the confidentiality, integrity or availability of the vulnerable environment. The exact impact depends on the installed version, exposed interfaces and deployment configuration.

Recommended administrator action

Confirm whether the affected product is present and compare installed versions with the vendor advisory and NVD record. Apply the vendor patch or documented mitigation; until remediation is complete, reduce exposure of affected interfaces, review relevant logs and monitor for indicators of exploitation. DataHouse can support version verification, managed patching, network exposure reduction, log review and backup validation for dedicated, cloud and colocated environments.

Sources

• NVD
• Reference