CVE-2026-6723

Appointment Booking Calendar <= 1.6.11.11 - Incorrect Authorization to Unauthenticated Sensitive Field Modification via Appointment Public Token

2026-10-09 15:56
awhacken

Strategic Overview

Status
Patched in 1.6.12.0
Affected Plugin
Simply Schedule Appointments
Affected Version
<= 1.6.11.11
CVSS
5.3Medium
Weakness type
CWE-863 · Incorrect Authorization
CVE
CVE-2026-6723
View all Simply Schedule Appointments vulnerabilities

At a glance

CVE-2026-6723 is a medium-severity Incorrect Authorization vulnerability in the Simply Schedule Appointments WordPress plugin, affecting versions <= 1.6.11.11. It carries a CVSS score of 5.3 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 1.6.12.0; sites on affected versions should update now. Disclosed October 2026, reported by awhacken.

Vulnerability Overview

The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin plugin for WordPress is vulnerable to Incorrect Authorization in all versions up to, and including, 1.6.11.11. This is due to the appointment update REST API endpoint not restricting which fields can be modified by token-authenticated customers. This makes it possible for unauthenticated attackers to modify admin-controlled fields on that appointment, including faking payment confirmation, reassigning the appointment to another user, and changing the service type.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site, and no interaction from a victim user.

CWE-863: Incorrect Authorization

Reaching this weakness in Simply Schedule Appointments <= 1.6.11.11 takes no account at all. Incorrect authorization means a permission check exists but evaluates the wrong thing, so it passes for callers it was meant to stop.

The action runs for users the code intended to exclude, with the same effect as having no check at all. For Simply Schedule Appointments the fix is 1.6.12.0: builds <= 1.6.11.11 are affected, anything from 1.6.12.0 onward is not.

Remediation

Update to version 1.6.12.0, or a newer patched version

How does WordSec protect against this?

This one needs no account at all, which puts it outside what login hardening can reach; WordSec's login security narrows the account-level paths around it, and the firewall is what inspects the request itself. None of that substitutes for the fix: Simply Schedule Appointments 1.6.12.0 closes this, and updating the plugin is the step that ends it.

  • Login Security
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2026-6723https://www.wordfence.com/threat-intel/vulnerabilities/id/b6f16178-1aa3-4af2-a125-74467bc57e70https://nvd.nist.gov/vuln/detail/CVE-2026-6723

Related records

Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C