CVE-2026-26929 is a security vulnerability identified in the Apache Airflow project, specifically affecting versions 3.0.0 through 3.1.7. The flaw resides in the FastAPI DagVersion listing API, which is responsible for providing metadata about Directed Acyclic Graphs (DAGs) used in workflow orchestration. When a request is made with the dag_id parameter set to "~", which acts as a wildcard for all DAGs, the API fails to apply proper per-DAG authorization filtering. This means that users can retrieve version metadata for DAGs they are not authorized to access, violating access control policies. The vulnerability is categorized under CWE-732, indicating incorrect permission assignment for critical resources, which can lead to unauthorized information disclosure. Although no exploits have been reported in the wild, the exposure of DAG version metadata can reveal sensitive operational details, potentially aiding attackers in reconnaissance or further attacks. The issue does not require bypassing authentication but exploits a logic flaw in access control enforcement. The Apache Software Foundation has addressed this vulnerability in Apache Airflow version 3.1.8, which implements correct authorization checks for the DagVersion API when handling wildcard dag_id requests. Users of affected versions are strongly advised to upgrade to mitigate this risk.

The primary impact of CVE-2026-26929 is unauthorized disclosure of sensitive metadata related to DAG versions within Apache Airflow environments. This information leakage can compromise confidentiality by revealing workflow structures, version histories, and potentially sensitive operational details that could be leveraged by attackers for reconnaissance or to craft targeted attacks. While the vulnerability does not directly allow modification or disruption of workflows, the exposure of internal metadata can weaken an organization's security posture. Organizations relying on Airflow for critical data pipelines, automated workflows, or business processes may face increased risk of information leakage to unauthorized users. This could lead to indirect impacts such as intellectual property theft, exposure of business logic, or facilitation of further attacks against the environment. Since exploitation does not require user interaction and can be triggered by authenticated users with access to the API, insider threats or compromised accounts could exploit this flaw. The absence of known exploits in the wild reduces immediate risk but does not eliminate the potential for future attacks.

To mitigate CVE-2026-26929, organizations should upgrade Apache Airflow to version 3.1.8 or later, where the vulnerability has been fixed by enforcing proper per-DAG authorization filtering in the DagVersion listing API. Until the upgrade can be performed, administrators should consider restricting access to the FastAPI endpoints to trusted users only, using network-level controls such as firewall rules or API gateway policies to limit exposure. Implementing strict role-based access control (RBAC) and monitoring API usage logs for unusual access patterns can help detect attempts to exploit this vulnerability. Additionally, reviewing and minimizing the number of users with API access reduces the attack surface. Organizations should also ensure that their Airflow deployment follows security best practices, including using secure authentication mechanisms, encrypting communications, and regularly auditing permissions. Finally, staying informed about updates from the Apache Software Foundation and applying security patches promptly is critical to maintaining a secure environment.