Apache Airflow: JSON Variable secrets shown in cleartext in the Rendered Templates view

Impact

The secrets masker guards its redaction with an isinstance(str) check, so a Variable whose JSON value is a dict passes through unmasked when referenced via var.json in a template. Anyone with access to that task's Rendered Templates page reads the secret verbatim. Airflow is commonly the thing that launches training and ETL jobs onto a GPU fleet, and the credentials people park in JSON Variables are exactly the high-value ones: object-store keys, registry pull secrets, cluster and scheduler tokens. Disclosure is to authenticated Airflow users who may legitimately hold only DAG-read permissions, so this widens who effectively holds the fleet's credentials.

Who can reach it

An authenticated Airflow user with permission to view a task's Rendered Templates page. No special role beyond that, and no network position beyond reach of the Airflow UI.

What to do

Upgrade to apache-airflow 3.3.1 or later, which masks nested Variable values regardless of type, and restart the API/webserver and schedulers. Upgrading does not undo the exposure: rotate every secret that was stored as a JSON Variable and referenced through var.json in a rendered template, and check access logs for who could have viewed those pages. No worker node drain or reboot needed.

References