Information
When errors occur in a Web application or before the application dispatch, an error message is displayed to the user. By default, the app server displays an exception stack dump of the error. A default error handler or page should be defined for all applications.
Without a default error page, displaying the exception stack may reveal information about the application. For example, the names of classes and methods that are in the stack information. The exception message text is also displayed which could contain sensitive information.
Solution
Add the default-error-page attribute on the web-ext element for all webApplication elements in ${server.config.dir}/configDropins/overrides/*.xml and set it to a valid error page.
<webApplication ... >
<web-ext default-error-page="errorPageName.jsp"/>