NCH Express Invoice 8.06 to 8.24 is vulnerable to Reflected XSS in the Quotes List module.

In NCH Express Invoice 7.25, an authenticated low-privilege user can enter a crafted URL to access higher-privileged functionalities such as the "Add New Item" screen.

NCH Express Invoice 7.25 allows local users to discover the cleartext password by reading the configuration file.

In NCH Express Invoice v7.12, persistent cross site scripting (XSS) exists via the Invoices/Items/Customers/Quotes input field. An authenticated unprivileged user can add/modify the Invoices/Items/Customers fields parameter to inject arbitrary JavaScript.