Apache Airflow v3.0-3.1.8 DagRun API leaks XCom to Viewer role
CVE-2026-34538 Published on April 9, 2026
Apache Airflow: Authorization bypass in DagRun wait endpoint (XCom exposure)
Apache Airflow versions 3.0.0 through 3.1.8 DagRun wait endpoint returns XCom result values even to users who only have DAG Run read permissions, such as the Viewer role.This behavior conflicts with the FAB RBAC model, which treats XCom as a separate protected resource, and with the security model documentation that defines the Viewer role as read-only.
Airflow uses the FAB Auth Manager to manage access control on a per-resource basis. The Viewer role is intended to be read-only by default, and the security model documentation defines Viewer users as those who can inspect DAGs without accessing sensitive execution results.
Users are recommended to upgrade to Apache Airflow 3.2.0 which resolves this issue.
Vulnerability Analysis
CVE-2026-34538 is exploitable with network access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality, with no impact on integrity and availability.
Weakness Type
Exposure of Resource to Wrong Sphere
The product exposes a resource to the wrong control sphere, providing unintended actors with inappropriate access to the resource.
Products Associated with CVE-2026-34538
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Affected Versions
Apache Software Foundation Apache Airflow:- Version 3.0.0 and below 3.2.0 is affected.