The Simply Schedule Appointments WordPress plugin is affected by a stored cross-site scripting (XSS) vulnerability in the 'status' parameter in all versions up to and including 1.6.12.35. This vulnerability allows unauthenticated attackers to inject malicious scripts that execute when an administrator views the debug-log viewer, which is accessible with the site-wide Support PIN. The issue arises due to insufficient input sanitization and output escaping combined with debug logging enabled by default.
The Simply Schedule Appointments Booking Plugin for WordPress contains an incorrect authorization vulnerability in all versions up to and including 1.6.11.11. The flaw allows unauthenticated attackers to modify admin-controlled fields of appointments via the appointment update REST API endpoint. This includes faking payment confirmation, reassigning appointments to other users, and changing service types.
Simply Schedule Appointments WordPress plugin versions up to 1.6.12.31 contain an authorization bypass vulnerability via the 'complete_group' parameter. Authenticated users with subscriber-level access or higher can exploit missing validation on a user-controlled key to access private appointment tokens and personally identifiable information (PII) of co-bookers. Attackers can then use leaked tokens to read, modify, or cancel appointments of other users within the same group booking.
The Simply Schedule Appointments WordPress plugin up to version 1.6.12.32 has a missing authorization vulnerability via the 'recursive' parameter. This allows unauthenticated attackers to access sensitive customer information including names, emails, phone numbers, and custom form data. Additionally, attackers can obtain per-appointment public_token values that enable deletion of arbitrary appointments without authentication.
The Simply Schedule Appointments plugin for WordPress is vulnerable to Local File Inclusion in all versions up to, and including, 1.6.12.27 via the 'ssa_locale' parameter parameter. This makes it possible for authenticated attackers, with subscriber-level access and above, to include and execute arbitrary .php files on the server, allowing the execution of any PHP code in those files. This can be used to bypass access controls, obtain sensitive data, or achieve code execution in cases where .php file types can be uploaded and included. Notably, exploitation does not require authentication in practice, as the locale filter is installed unconditionally on every request during plugins_loaded and the callback performs no nonce or capability check before returning the raw GET parameter value.
The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 1.6.12.10 via the ssa_past_appointments due to missing validation on a user controlled key. This makes it possible for authenticated attackers, with contributor-level access and above, to access appointment records belonging to arbitrary users and harvest the per-appointment ownership tokens (32-character hashes) embedded in the rendered HTML, which can then be used without any authentication to read or modify those appointments including full customer PII such as name, email, phone number, and private notes. The /wp-json/ssa/v1/render-shortcode REST endpoint is registered unconditionally on rest_api_init regardless of whether the Divi theme is installed, and its permission callback only requires current_user_can('edit_posts'), meaning any Contributor-level account is sufficient to trigger this entire exploit chain.
The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin plugin for WordPress is vulnerable to Missing Authorization in all versions up to, and including, 1.6.11.8 due to the plugin not properly verifying that a user is authorized to perform an action via the bulk appointments REST API endpoint. This makes it possible for unauthenticated attackers to modify arbitrary appointment records including customer PII, payment status, and meeting URL fields, and to expose full customer PII from existing appointment records via the bulk endpoint response. The public nonce is a static, user-independent value present in the HTML source of any page hosting the [ssa_booking] shortcode, meaning any visitor who has viewed such a page can obtain it and target any appointment in the system without authentication.
The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin plugin for WordPress is vulnerable to time-based blind SQL Injection via the 'append_where_sql' parameter in all versions up to, and including, 1.6.11.8 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. The /appointments/bulk REST endpoint is reachable by unauthenticated attackers because its permission check accepts a public nonce that is embedded in the booking widget's frontend JavaScript (ssa.api.public_nonce) and visible to all site visitors; exploitation requires issuing the request as a PUT with an application/x-www-form-urlencoded body so that PHP's superglobals are not populated and the blocklist check silently passes.
The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin plugin for WordPress is vulnerable to denial of service in all versions up to, and including, 1.6.11.5. This is due to a publicly accessible REST API endpoint (/wp-json/ssa/v1/async) that calls PHP's sleep() function on a user-supplied delay parameter without any rate limiting. This makes it possible for unauthenticated attackers to exhaust PHP worker processes, denying access to the site to legitimate users.
The Appointment Booking Calendar plugin for WordPress is vulnerable to Missing Authorization in versions up to and including 1.6.10.6. This is due to a flawed authorization logic in the nonce_permissions_check() method combined with the public exposure of a site-wide reusable nonce. The plugin exposes a public_nonce value through the /wp-json/ssa/v1/embed-inner endpoint, which is accessible to unauthenticated users. The appointment deletion endpoint at /wp-json/ssa/v1/appointments/{id}/delete and /wp-json/ssa/v1/appointments/bulk use a permission check that accepts requests containing both an X-WP-Nonce header (with any arbitrary value) and an X-PUBLIC-Nonce header (with the valid public nonce). When the X-WP-Nonce validation fails, the function falls back to validating the X-PUBLIC-Nonce without properly rejecting the request. Since the public_nonce is exposed to all unauthenticated visitors and is site-wide (not user-specific or appointment-specific), attackers can obtain it and use it to view details of arbitrary appointments, including the public_edit_url, or delete arbitrary appointments by ID. This makes it possible for unauthenticated attackers to view, delete or modify any appointment in the system, disclosing sensitive appointment data, causing service disruption, and loss of booking records.
The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin plugin for WordPress is vulnerable to SQL Injection via the 'fields' parameter in all versions up to, and including, 1.6.10.0 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, including usernames, email addresses, and password hashes.
The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 1.6.9.29. This is due to the `get_item_permissions_check` method granting access to users with the `ssa_manage_appointments` capability without validating staff ownership of the requested appointment. This makes it possible for authenticated attackers, with custom-level access and above (users granted the ssa_manage_appointments capability, such as Team Members), to view appointment records belonging to other staff members and access sensitive customer personally identifiable information via the appointment ID parameter.
The Appointment Booking Calendar — Simply Schedule Appointments plugin for WordPress is vulnerable to unauthorized access of sensitive data in all versions up to and including 1.6.9.29. This is due to two compounding weaknesses: (1) a non-user-bound `public_nonce` is exposed to unauthenticated users through the public `/wp-json/ssa/v1/embed-inner` REST endpoint, and (2) the `get_item()` method in `SSA_Settings_Api` relies on `nonce_permissions_check()` for authorization (which accepts the public nonce) but does not call `remove_unauthorized_settings_for_current_user()` to filter restricted fields. This makes it possible for unauthenticated attackers to access admin-only plugin settings including the administrator email, phone number, internal access tokens, notification configurations, and developer settings via the `/wp-json/ssa/v1/settings/{section}` endpoint. The exposure of appointment tokens also allows an attacker to modify or cancel appointments.
The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin plugin for WordPress is vulnerable to blind SQL Injection in all versions up to, and including, 1.6.9.27. This is due to the `db_where_conditions` method in the `TD_DB_Model` class failing to prevent the `append_where_sql` parameter from being passed through JSON request bodies, while only checking for its presence in the `$_REQUEST` superglobal. This makes it possible for unauthenticated attackers to append arbitrary SQL commands to queries and extract sensitive information from the database via the `append_where_sql` parameter in JSON payloads granted they have obtained a valid `public_token` that is inadvertently exposed during the booking flow.
The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin plugin for WordPress is vulnerable to blind SQL Injection via the `order` and `append_where_sql` parameters in all versions up to, and including, 1.6.9.9 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.
The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin plugin for WordPress is vulnerable to Sensitive Information Exposure in all versions up to, and including, 1.6.9.5 via the hash() function due to use of a hardcoded fall-back salt. This makes it possible for unauthenticated attackers to generate a valid token across sites running the plugin that have not manually set a salt in the wp-config.php file and access booking information that will allow them to make modifications.
The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin for WordPress is vulnerable to Sensitive Information Exposure in all versions up to, and including, 1.6.9.16. This is due to the plugin exposing its admin embed endpoint at `/wp-json/ssa/v1/embed-inner-admin` without authentication, which leaks plugin settings including staff names, business names, and configuration data that are not publicly displayed on the booking form. This makes it possible for unauthenticated attackers to extract private business configuration. In premium versions with integrations configured, this might also expose other sensitive data including API keys for external services.
The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's ssa_admin_upcoming_appointments, ssa_admin_upcoming_appointments, and ssa_past_appointments shortcodes in all versions up to, and including, 1.6.8.30 due to insufficient input sanitization and output escaping on user supplied attributes. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin plugin for WordPress is vulnerable to arbitrary shortcode execution in all versions up to, and including, 1.6.8.5. This is due to the software allowing users to execute an action that does not properly validate a value before running do_shortcode. This makes it possible for unauthenticated attackers to execute arbitrary shortcodes.