Executive brief
Apache Airflow is an open-source platform used to schedule and monitor complex workflows. A vulnerability in the way it handles internal data sharing (XCom) allows users who can author workflows (DAGs) to execute unauthorized code on the central webserver. While workflow authors are typically trusted users, this flaw allows them to escalate their privileges and potentially compromise the entire Airflow environment or access sensitive data.
Technical details
A vulnerability exists in Apache Airflow's XCom API due to unsafe deserialization of untrusted data (CWE-502). The root cause is a bypass of legacy serialization key protections (specifically `__type` and `__var`) that occurred during a refactoring of the task-sdk and core dependencies. An attacker with DAG author privileges can craft a malicious XCom payload that, when processed by the webserver, triggers arbitrary code execution. This effectively allows a user with 'Low' privileges (in the context of network access/Airflow roles) to achieve Remote Code Execution (RCE) on the webserver. The issue is resolved in version 3.2.0 by re-implementing validation for reserved serialization keys.
Affected products
- Apache Airflow >= 3.1.8, < 3.2.0
Timeline
- 2026-03-27: patched: Fix merged into main branch via PR #64148
- 2026-04-13: advisory: Initial disclosure and CVE assignment