Vulnerability in Apache Airflow Scheduler Allows Unsafe Deserialization of Task Values

CVE-2026-86829

What is CVE-2026-86829?

Apache Airflow's scheduler is vulnerable due to the complete deserialization of XCom values generated by task code during the evaluation of task dependencies. This issue is significant as a Dag author can control the content written to XCom, which is subsequently deserialized within the scheduler process. The potential risk arises from the security model of Airflow, wherein a Dag author is treated as less trusted than the Deployment Manager. It is crucial for installations that restrict the trust levels of Dag authors to assess their configurations, especially when task dependencies involve task-written XCom values. Users are strongly encouraged to update to Apache Airflow version 3.4.0 or later, which enforces strict evaluation limitations on XCom values to mitigate this vulnerability.

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