Kibana versions before 6.8.9 and 7.7.0 contains a stored XSS flaw in the TSVB visualization. An attacker who is able to edit or create a TSVB visualization could allow the attacker to obtain sensitive information from, or perform destructive actions, on behalf of Kibana users who edit the TSVB visualization.
To mitigate this vulnerability you can set "metrics.enabled: false" in kibana.yml