The WP-WebAuthn plugin for WordPress is vulnerable to Unauthenticated Stored Cross-Site Scripting via the wwa_auth AJAX endpoint in all versions up to, and including, 1.3.4 due to insufficient input sanitization and output escaping on user supplied attributes logged by the plugin. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses the plugin's log page, provided that the logging option is enabled in the plugin settings.