The Online Scheduling and Appointment Booking System – Bookly WordPress plugin is affected by a PHP Object Injection vulnerability through deserialization of untrusted input in the 'value' parameter. This affects all versions up to and including 28.2. The vulnerability requires authenticated attackers with custom-level access or higher. No known exploit gadget chains are currently available. The vulnerability has a high severity rating with a CVSS score of 7.2.
CVE-2026-103365 is a medium severity vulnerability in the Bookly Online Scheduling and Appointment Booking System WordPress plugin up to version 28.4. It allows unauthenticated attackers to access sensitive customer information by exploiting an endpoint that improperly validates requests and uses attacker-supplied identifiers to retrieve personal data. This exposure includes customer names, emails, phone numbers, and internal notes when certain placeholders are used in the booking form's Details step.
The Bookly plugin for WordPress up to version 28.4 contains an authorization bypass vulnerability due to insecure direct object reference via user-controlled parameters. Authenticated users with subscriber-level access or higher can exploit this flaw to overwrite the WordPress account binding of any Bookly staff record, including administrators, leading to privilege escalation. Exploitation requires the attacker to be linked to at least one Bookly staff record, which is enabled by default on fresh installs with a specific option active.
The Bookly plugin for WordPress is vulnerable to Insecure Direct Object Reference in versions up to, and including, 28.2 via the 'bookly_get_form_id', 'bookly_render_complete', 'bookly_add_to_calendar' and 'bookly_rollback_order' AJAX actions. This is due to the 'bookly_get_form_id' handler blindly storing the attacker-controlled 'order_id' from the submitted form_data into a new booking session, which the 'bookly_render_complete' handler then trusts to look up and return the corresponding Order's secret token without verifying that the current session created that order. This makes it possible for unauthenticated attackers to enumerate sequential order IDs, disclose other customers' order tokens, retrieve calendar/appointment information via 'bookly_add_to_calendar' and permanently delete arbitrary non-completed bookings via 'bookly_rollback_order', which cascade-deletes the customer_appointment and (when no other customers are attached) the underlying appointment.
The Online Scheduling and Appointment Booking System – Bookly plugin for WordPress is vulnerable to Authorization Bypass via PHP Type Juggling in all versions up to, and including, 28.2. This is due to the `postValidateCustomer()` function using a loose PHP inequality operator (`!=`) to compare the session-stored one-time verification code against the attacker-supplied `verification_code` parameter — a flaw that is further exposed by the booking AJAX controller registering all its methods as `wp_ajax_nopriv_` handlers and unconditionally overriding `csrfTokenValid()` to return true, leaving the endpoint both unauthenticated and CSRF-unprotected. This makes it possible for unauthenticated attackers to bypass the phone/email ownership verification step and overwrite the name, email, phone, and address fields of any arbitrary existing Bookly customer record, redirecting that customer's booking notifications to attacker-controlled contact details. The bypass is achievable because the `json_data` input channel decodes input via `json_decode()`, which preserves real PHP types and causes the `wp_kses` filter to leave non-string values such as the JSON boolean `true` untouched; submitting `true` as the `verification_code` satisfies the loose comparison against the session's non-zero integer code (generated by `mt_rand(100000, 999999)`), causing `true != <non-zero int>` to evaluate as `false` and the guard to be bypassed.
The Bookly plugin for WordPress (Online Scheduling and Appointment Booking System) up to version 28.1 suffers from an authorization bypass vulnerability via the 'conversation_id' parameter. This allows unauthenticated attackers to enumerate and access AI booking conversation transcripts of any customer, exposing sensitive personal information such as names, emails, phone numbers, and appointment details. Attackers can also inject arbitrary messages into victim conversations, which are replayed to the AI worker. The vulnerability arises from missing validation on a user-controlled key and the use of sequential integer conversation IDs without ownership or session identifiers.
The Online Scheduling and Appointment Booking System – Bookly plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the 'updateAddon' function in all versions up to, and including, 27.2. This makes it possible for authenticated attackers, with Subscriber-level access and above, to update any plugin with a main file of 'main.php' to its latest version.
The Online Scheduling and Appointment Booking System – Bookly plugin for WordPress is vulnerable to Stored Cross-Site Scripting via bookly_speed_up_update_addons AJAX action in all versions up to, and including, 27.7 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The injection point is the bookly_speed_up_update_addons AJAX action, which is registered as wp_ajax_nopriv_* and therefore reachable without authentication; the payload is stored verbatim in the bookly_log.details column when a request is submitted without a valid signature, and executes when an administrator later views the Diagnostics → Logs page.
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.
The Online Scheduling and Appointment Booking System – Bookly plugin for WordPress is vulnerable to time-based SQL Injection via the 'staff_ids' parameter in all versions up to, and including, 27.5 due to insufficient escaping on the user supplied parameter and lack of sufficient preparation on the existing SQL query. This makes it possible for unauthenticated attackers to append additional SQL queries into already existing queries that can be used to extract sensitive information from the database. Exploitation requires a two-request chain: an attacker first calls the unauthenticated bookly_get_form_id action to seed a booking session carrying malicious staff_ids values, then triggers bookly_render_time to cause the tainted array to reach the vulnerable query; CSRF/nonce validation is absent on both endpoints, meaning this chain can be initiated cross-site.
The Online Scheduling and Appointment Booking System – Bookly plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'bookly-customer-full-name' cookie in versions up to, and including, 27.2 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. Exploitation requires 'Remember personal information in cookies' setting to be enabled (disabled by default).
The Online Scheduling and Appointment Booking System – Bookly plugin for WordPress is vulnerable to price manipulation via the 'tips' parameter in all versions up to, and including, 27.0. This is due to the plugin trusting a user-supplied input without server-side validation against the configured price. This makes it possible for unauthenticated attackers to submit a negative number to the 'tips' parameter, causing the total price to be reduced to zero.
The WordPress Online Booking and Scheduling Plugin – Bookly plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the Color Profile parameter in all versions up to, and including, 23.2 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with the staff member role and Subscriber-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.