Description
Apache Airflow's scheduler-side deadline-reference decoder (`SerializedCustomReference.deserialize_reference`) imported and dispatched arbitrary class paths drawn from DAG-author-controlled serialized state without an allowlist or plugin-registry gate. A DAG author whose code reaches the scheduler — the default on single-host deployments where the DAG bundle is importable from the scheduler process — could embed a custom `DeadlineReference` whose serialized form named an attacker-controlled module path, causing the scheduler to `import_string(...)` and instantiate that class with a live SQLAlchemy session attached. Affects deployments where DAG-author code is less trusted than the scheduler process. Users are advised to upgrade to `apache-airflow` 3.2.2 or later.
Problem types
CWE-502: Deserialization of Untrusted Data
Product status
Any version before 3.2.2
Credits
Jarek Potiuk
References
www.openwall.com/lists/oss-security/2026/05/31/12
github.com/apache/airflow/pull/66737
lists.apache.org/thread/q227dghjwgfz8xsxrf2pwpz4wk43zm83