In Apache Airflow versions before 3.1.6, when rendered template fields in a Dag exceed [core] max_templated_field_length, sensitive values could be exposed in cleartext in the Rendered Templates UI. This occurred because serialization of those fields used a secrets masker instance that did not include user-registered mask_secret() patterns, so secrets were not reliably masked before truncation and display. Users are recommended to upgrade to 3.1.6 or later, which fixes this issue
Apache Airflow secrets in rendered templates could contain parts of sensitive values when truncated
Apache Airflow: Secrets in rendered templates could contain parts of sensitive values when truncated