Seo Redirection Plugin Cross-site Scripting

The SEO Redirection Plugin – 301 Redirect Manager WordPress plugin before 6.4 did not sanitise the Redirect From and Redirect To fields when creating a new redirect in the dashboard, allowing high privilege users (even with the unfiltered_html disabled) to set XSS payloads (2021-05-17, CVE-2021-24327)

The tab parameter of the settings page of the 404 SEO Redirection WordPress plugin through 1.3 is vulnerable to a reflected Cross-Site Scripting (XSS) issue as user input is not properly sanitised or escaped before being output in an attribute. (2021-05-17, CVE-2021-24325)

Cross site scripting is an attack where a web page executes code that is injected by an adversary. It usually appears, when users input is presented. This attack can be used to impersonate a user, take over control of the session, or even steal API keys.

The attack can be executed e.g. when you application injects the request parameter directly into the HTML code of the page returned to the user:

https://server.com/confirmation?message=Transaction+Complete

what results in:

<span>Confirmation: Transaction Complete</span>

In that case the message can be modified to become a valid Javascript code, e.g.:

https://server.com/confirmation?message=<script>dangerous javascript code here</script>

and it will be executed locally by the user's browser with full access to the user's personal application/browser data:

<span>Confirmation: <script>dangerous javascript code here</script></span>