safe-redirect is a library which resolves open-redirection vulnerability when we need to make client-side redirection to a path taken from query string.

For example, we have /login page and after successful login we need to redirect user to a path. Referrer can state the redirection path using callback query string parameter. Url looks like:

https://domain.com/login?callback=/payment

In /login page, after successful login, we implement the aforementioned requirement in this way:

// successful login
const path = new URLSearchParams(window.location.search).get("callback");
window.location.assign(path);

And here we have a open-redirection vulnerability

https://fake.com can redirect user to domain.com/login?callback=https://fake.com/fake , after successful login, the user will be redirected to https://fake.com/fake.

A site can redirect user to domain.com/login?callback=javascript:alert(document.cookie) and execute custom javascript code. (sensitive user data can be stolen, etc).

safe-redirect library solves this vulnerability. Simply:

npm i @trendyol-js/safe-redirect

import { redirect } from "@trendyol-js/safe-redirect";

// successful login
redirect("callback"); // give name of the query parameter