The plugin does not sanitise and escape some of its settings, which could allow high privilege users such as admin to perform Stored Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed (for example in multisite setup).
1. Go to "Cognito Login ยป Configure OAuth", and add an application.
2. Then go to "Cognito Login ยป Attribute/Role Mapping" and in the Username add the payload: xss'"><script>alert(/XSS/);</script>"'
3. Click "Save settings" to check the XSS popup.