Apache Airflow: deadline alert fields let Dag authors construct allow-listed classes in the scheduler

Impact

Airflow rebuilt deadline alert fields from the serialized Dag through generic deserialization, which imports and instantiates the class named in the payload. A Dag author can make the scheduler and API server construct classes on Airflow's deserialization allow list with arguments they control. These processes run with more privilege than the worker-scoped execution a Dag author is supposed to have. This is an incomplete fix of CVE-2026-45360: that fix only hardened the reference field and left callback and interval exposed.

Who can reach it

A Dag author who can deploy Dags that use deadline alerts. Authentication (Dag deployment rights) is required.

What to do

Upgrade to apache-airflow 3.4.0 or later and restart the scheduler and API server. Deployments that only applied the CVE-2026-45360 fix are still affected.

References

Related entries

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