The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the ‘link’ parameter in versions up to, and including, 1.6.7.14 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with contributor-level permissions 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 Reflected Cross-Site Scripting via the accentcolor and background parameter in all versions up to, and including, 1.6.8.3 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link.

The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin plugin for WordPress is vulnerable to SQL Injection via the customerid parameter in all versions up to, and including, 1.6.7.7 due to insufficient escaping on the user supplied parameter and lack of sufficient preparation on the existing SQL query. This makes it possible for authenticated attackers, with contributor access or higher, 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 Cross-Site Request Forgery in all versions up to, and including, 1.6.6.20. This is due to missing or incorrect nonce validation on the ssafactoryreset() function. This makes it possible for unauthenticated attackers to reset the plugin's settings via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.

The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's ssaadminupcomingappointments, ssaadminupcomingappointments, and ssapastappointments 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 WordPress plugin before 1.6.7.55 does not sanitise and escape some of its Appointment Type settings, which could allow high privilege users such as admin to perform Cross-Site Scripting attacks even when unfilteredhtml is disallowed

The Appointment Booking Calendar — Simply Schedule Appointments Booking Plugin WordPress plugin before 1.6.7.55 does not sanitise and escape some of its Notification settings, which could allow high privilege users such as admin to perform Cross-Site Scripting attacks even when unfilteredhtml is disallowed

The Simply Schedule Appointments WordPress plugin before 1.5.7.7 does not sanitise and escape some of its settings, which could allow high privilege users such as admin to perform Stored Cross-Site Scripting attacks even when the unfilteredhtml capability is disallowed (for example in multisite setup)

The Simply Schedule Appointments WordPress plugin before 1.5.7.7 is missing authorisation in a REST endpoint, allowing unauthenticated users to retrieve WordPress users details such as name and email address