CVE-2026-26929: 
Apache Airflow vulnerability analysis and mitigation

CVE-2026-26929 is an authorization bypass vulnerability in Apache Airflow's FastAPI DagVersion listing API, titled "Wildcard DagVersion Listing Bypasses Per-DAG RBAC and Leaks Metadata." It affects Apache Airflow versions 3.0.0 through 3.1.7, where the API fails to enforce per-DAG authorization filtering when the dag_id parameter is set to "~" (the wildcard for all DAGs), causing version metadata of unauthorized DAGs to be returned to the requester. The vulnerability was disclosed on March 17, 2026, and has a CVSS v3.1 base score of 6.5 (Medium) (Feedly, oss-security).

The root cause is an incorrect permission assignment for a critical resource (CWE-732): the FastAPI route handling DagVersion listing in airflow/api_fastapi/core_api/routes/public/dag_versions.py did not apply RBAC filtering based on the authenticated user's DAG-level read permissions when the wildcard dag_id=~ was used. An authenticated user with low privileges can send a crafted GET request to the DagVersion listing API endpoint with dag_id set to "~", bypassing per-DAG authorization checks and receiving version metadata for all DAGs, including those they are not permitted to access. The fix, contributed by Pierre Jeambrun and merged February 10, 2026, ensures that even wildcard requests are filtered against the user's readable DAG permissions (GitHub PR, oss-security).

Successful exploitation results in unauthorized disclosure of DAG version metadata, impacting confidentiality (CVSS C:H) with no impact on integrity or availability. An authenticated but low-privileged user can enumerate version metadata — such as DAG names, version identifiers, and structural information — for all DAGs in the Airflow instance, including those belonging to other teams or containing sensitive workflow logic. This information leakage could facilitate further reconnaissance or privilege escalation within the Airflow environment (Feedly, oss-security).

1. Reconnaissance: Identify an Apache Airflow instance running versions 3.0.0 through 3.1.7 with the FastAPI-based REST API exposed (default in Airflow 3.x).
2. Authentication: Obtain valid credentials for any low-privilege Airflow user account (e.g., a user with access to only a subset of DAGs).
3. Craft the request: Send an authenticated GET request to the DagVersion listing API endpoint with the dag_id parameter set to the wildcard value "~", for example: GET /api/v1/dagVersions?dag_id=~.
4. Receive unauthorized data: The API returns version metadata for all DAGs in the system, including those the authenticated user is not authorized to view, bypassing per-DAG RBAC controls.
5. Enumerate sensitive information: Review the returned metadata (DAG names, version IDs, timestamps, etc.) to map the Airflow environment and identify potentially sensitive workflows for further targeting (GitHub PR, oss-security).

• Network: Authenticated HTTP GET requests to the DagVersion listing API endpoint (e.g., /api/v1/dagVersions or equivalent FastAPI route) with dag_id=~ from users who do not have broad DAG access permissions.
• Logs: Airflow API access logs showing repeated or unusual requests to the DagVersion endpoint with wildcard parameters from low-privilege user accounts; responses returning large volumes of DAG version records inconsistent with the user's authorized DAG set.
• Application Behavior: A low-privilege user account receiving DAG version metadata for DAGs outside their assigned access scope, observable via Airflow audit logs if enabled.

The primary remediation is to upgrade Apache Airflow to version 3.1.8 or later, which applies proper per-DAG RBAC filtering for wildcard DagVersion listing requests. No configuration-based workaround has been officially documented; restricting API access to trusted networks or requiring stronger authentication controls can reduce exposure until patching is feasible. Organizations should audit Airflow API access logs for anomalous wildcard DagVersion requests from low-privilege accounts as a precautionary measure (oss-security, GitHub PR).

The vulnerability was disclosed via the Apache oss-security mailing list on March 17, 2026, with severity rated as "low" by the reporter Rahul Vats, though the CVSS score reflects a Medium/High confidentiality impact. The fix was credited to Pierre Jeambrun of Astronomer. Coverage has been limited to vulnerability aggregator sites and security databases, with no notable broader media or researcher commentary identified (oss-security).