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PatchSiren cyber security CVE debrief

CVE-2026-11866 WordPress CVE debrief

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. This allows 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. The vulnerability affects WordPress sites using the Appointment Booking Plugin and requires immediate attention to prevent potential security breaches.

Vendor
WordPress
Product
Appointment Booking Plugin
CVSS
MEDIUM 5.4
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-16
Original CVE updated
2026-07-16
Advisory published
2026-07-16
Advisory updated
2026-07-16

Who should care

Administrators of WordPress sites using the Appointment Booking Plugin should verify that their plugin is up-to-date and consider implementing additional security measures to protect against CSRF attacks. They should also review the official CVE record and NVD detail page for the latest information and guidance on remediation.

Technical summary

The Appointment Booking Plugin for WordPress is vulnerable to Cross-Site Request Forgery (CSRF) attacks due to a lack of CSRF nonce validation on several state-changing actions. This allows attackers to perform privileged actions, such as overwriting the booking-form configuration or disconnecting the connected payment gateway, against a logged-in administrator. The vulnerability affects WordPress sites using the Appointment Booking Plugin before version 5.6.3.

Defensive priority

High

Recommended defensive actions

  • Update the Appointment Booking Plugin to version 5.6.3 or later
  • Implement additional security measures to protect against CSRF attacks, such as validating user requests and using secure tokens
  • Monitor your WordPress site for suspicious activity and report any issues to the plugin vendor
  • Review compensating controls for exposed systems while remediation is scheduled and verified
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record was published on 2026-07-16T07:16:46.593Z and has not been modified since then. The NVD entry is currently in the 'Received' status. The source item URL for CVE-2026-11866 is provided, but additional verification is needed to confirm affected scope and severity. Defenders should verify the official CVE record and NVD detail page for the latest information.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-11866 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-11866

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-11866 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-11866

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.