include::../description.adoc[]

include::../ask-yourself.adoc[]

include::../recommended.adoc[]

== Sensitive Code Example

In Express.js application the code is sensitive if the https://www.npmjs.com/package/helmet[helmet] ``referrerPolicy`` middleware is disabled or used with ``no-referrer-when-downgrade`` or ``unsafe-url``:

----
const express = require('express');
const helmet = require('helmet');

app.use(
  helmet.referrerPolicy({ 
    policy: 'no-referrer-when-downgrade' // Sensitive: no-referrer-when-downgrade is used
  })
);
----

== Compliant Solution

In Express.js application a secure solution is to user the https://www.npmjs.com/package/helmet[helmet] referrer policy middleware set to ``no-referrer``:

----
const express = require('express');
const helmet = require('helmet');

let app = express();

app.use(
  helmet.referrerPolicy({
    policy: 'no-referrer' // Compliant
  })
); 
----

include::../see.adoc[]