Online Scheduling and Appointment Booking System – Bookly <= 27.7 - Authenticated (Staff+) Insecure Direct Object Reference to Sensitive Information Exposure via 'params[id]' Parameter
Strategic Overview
- Status
- Patched in 28.0
- Affected Plugin
- Online Scheduling and Appointment Booking System – Bookly
- Affected Version
<= 27.7- CVSS
- 4.3Medium
- Weakness type
- CWE-639 · Authorization Bypass Through User-Controlled Key
- CVE
CVE-2026-12905
At a glance
CVE-2026-12905 is a medium-severity Authorization Bypass Through User-Controlled Key vulnerability in the Online Scheduling and Appointment Booking System WordPress plugin, affecting versions <= 27.7. It carries a CVSS score of 4.3 (reachable over the network; low attack complexity). Exploitation requires an authenticated account at Staff level or above. The issue is fixed in version 28.0; sites on affected versions should update now. Disclosed August 2026, reported by Raihan Adi Arba.
Vulnerability Overview
The Bookly plugin for WordPress is vulnerable to Insecure Direct Object Reference in versions up to, and including, 27.7 via the appointment() method of the Mobile Staff Cabinet API (resource=appointment, action=bookly_mobile_staff_cabinet) in frontend/modules/mobile_staff_cabinet/api/handlers/Handler1_0.php. This is due to the handler loading an Appointment by the attacker-supplied params[id] without verifying that the appointment's staff_id matches the authenticated staff member, whereas sibling operations (deleteAppointment, saveAppointment, appointments list) correctly scope to $this->staff->getId() when $this->role === ROLE_STAFF. This makes it possible for authenticated attackers, with staff-level mobile cabinet access (any valid access_key token bound to a Staff entity), to read appointment details — including the internal note and the full customer_appointments collection (customer full_name, email, phone, notes, custom_fields, extras, payment_total, payment_type, payment_status) — belonging to other staff members by enumerating sequential appointment IDs.
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 interaction from a victim user.
CWE-639: Authorization Bypass Through User-Controlled Key
Online Scheduling and Appointment Booking System <= 27.7 carries this weakness at appointment(), and reaching it takes an account at Staff level or above. 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 Online Scheduling and Appointment Booking System the fix is 28.0: builds <= 27.7 are affected, anything from 28.0 onward is not.
Remediation
Update to version 28.0, or a newer patched version
How does WordSec protect against this?
Because it turns on account access, WordSec's login security is the relevant layer: role-based two-factor, captcha and brute-force limits raise the cost of getting the account this needs. None of that substitutes for the fix: Online Scheduling and Appointment Booking System 28.0 closes this, and updating the plugin is the step that ends it.
- Login Security
- Alerts
External References
Related records
Other vulnerabilities in Online Scheduling and Appointment Booking System – Bookly
- 8.1CVE-2023-26526: Bookly <= 21.7.1 Arbitrary File Deletion
CVE-2023-26526 - 7.5CVE-2026-13395: Online Scheduling and Appointment… SQL Injection
CVE-2026-13395 - 7.5CVE-2026-61949: Online Scheduling and Appointment… SQL Injection
CVE-2026-61949 - 7.2CVE-2026-13424: Online Scheduling and Appointment… Stored XSS
CVE-2026-13424 - 7.2CVE-2026-61944: Online Scheduling and Appointment… Stored XSS
CVE-2026-61944 - 7.2CVE-2026-5513: Online Scheduling and Appointment… Stored XSS
CVE-2026-5513 - 7.2CVE-2023-1172: Bookly <= 21.5 Stored Cross-Site Scripting
CVE-2023-1172 - 7.2CVE-2018-6891: WordPress Online Booking… XSS
CVE-2018-6891
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