CVE-2026-9188

Appointment Bookings for Zoom GoogleMeet and more – Wappointment <= 2.7.6 - Unauthenticated Insecure Direct Object Reference via Predictable 'edit_key' / 'appointmentkey' Parameter

2026-07-01 20:20
davidfdzmorilla

Strategic Overview

Status
Patched in 2.7.7
Affected Version
<= 2.7.6
CVSS
5.3Medium
Weakness type
CWE-639 · Authorization Bypass Through User-Controlled Key
CVE
CVE-2026-9188
View all Appointment Bookings for Zoom GoogleMeet and more – Wappointment vulnerabilities

At a glance

CVE-2026-9188 is a medium-severity Authorization Bypass Through User-Controlled Key vulnerability in the Appointment Bookings for Zoom GoogleMeet and more WordPress plugin, affecting versions <= 2.7.6. 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 2.7.7; sites on affected versions should update now. Disclosed July 2026, reported by davidfdzmorilla.

Vulnerability Overview

The Appointment Bookings for Zoom GoogleMeet and more – Wappointment plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to and including 2.7.6 via the `appointmentkey` parameter due to the appointment `edit_key` — the sole authorization token consumed by `tryCancel()` — being generated as a predictable, unsalted MD5 hash of only `client_id` (a sequential integer), `start_at` (a publicly observable appointment timestamp), and `staff_id` (a small enumerable integer), with no secret salt or random component, and the unauthenticated cancellation and rescheduling REST endpoints performing no ownership or identity verification beyond matching this reconstructible key. This makes it possible for unauthenticated attackers to compute valid `edit_key` values for appointments belonging to other users and cancel or reschedule those appointments arbitrarily. Exploitation requires the `allow_cancellation` or `allow_rescheduling` setting to be enabled on the site, both of which are common configurations for active booking deployments; an attacker can obtain the inputs needed to reconstruct a victim's key by booking their own appointment to observe their sequential `client_id` and correlating publicly visible appointment times and enumerable staff identifiers.

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-639: Authorization Bypass Through User-Controlled Key

Appointment Bookings for Zoom GoogleMeet and more <= 2.7.6 carries this weakness at tryCancel(), and reaching it takes no account at all. Authorization bypass through a user-controlled key, often called insecure direct object reference, means the application looks up a record by an identifier from the request without checking that the caller owns it.

Changing a number in the request is enough to read or modify other users' records, which on commerce and membership sites means customer data. For Appointment Bookings for Zoom GoogleMeet and more the fix is 2.7.7: builds <= 2.7.6 are affected, anything from 2.7.7 onward is not.

Remediation

Update to version 2.7.7, 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: Appointment Bookings for Zoom GoogleMeet and more 2.7.7 closes this, and updating the plugin is the step that ends it.

  • Login Security
  • Alerts

External References

Related records

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