The Genzel breadcrumbs plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 1.2. This is due to missing or incorrect nonce validation on the _options_page function. This makes it possible for unauthenticated attackers to update the plugin's breadcrumb configuration, including templates, delimiter, home label, home URI, and breadcrumb rules via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.
https://plugins.trac.wordpress.org/browser/genzel-breadcrumbs/trunk/page-options.php#L16
https://plugins.trac.wordpress.org/browser/genzel-breadcrumbs/trunk/gb.class.php#L424
https://plugins.trac.wordpress.org/browser/genzel-breadcrumbs/trunk/gb.class.php#L412