In NCH Express Accounts 8.24 and earlier, an authenticated low-privilege user can enter a crafted URL to access higher-privileged functionalities such as Add/Edit users.
NCH Express Accounts 8.24 and earlier allows local users to discover the cleartext password by reading the configuration file.
In NCH Express Accounts Accounting v7.02, persistent cross site scripting (XSS) exists in Invoices/Sales Orders/Items/Customers/Quotes input field. An authenticated unprivileged user can add/modify the Invoices/Sales Orders/Items/Customers/Quotes fields parameter to inject arbitrary JavaScript.