Executive brief
A vulnerability in the Apache Airflow SFTP provider allows a malicious or compromised SFTP server to write files to unauthorized locations on the Airflow system. This occurs when Airflow is configured to download directories from an untrusted server, potentially allowing an attacker to overwrite sensitive system files or plant malicious code. No Airflow account is required for this attack to succeed, posing a risk to any deployment interacting with external SFTP sources.
Technical details
A path traversal vulnerability exists in the `SFTPHook.retrieve_directory` and `SFTPOperator(operation=get)` components of the Apache Airflow SFTP provider. The root cause is a failure to validate directory-entry names returned by a remote SFTP server, which can contain '..' components. An attacker controlling a remote SFTP server can craft these names to escape the local destination directory and write files to arbitrary locations on the host filesystem. This vulnerability can be exploited without authentication if an Airflow DAG is configured to download directories from the attacker-controlled server. The issue is resolved in version 5.8.1 by implementing a containment check that resolves computed local paths and ensures they remain within the intended destination.
Affected products
- Apache Software Foundation Apache Airflow SFTP provider < 5.8.1
Timeline
- 2026-06-04: patched: Pull request merged into Apache Airflow main branch
- 2026-06-16: disclosed: Mailing list announcement on oss-security
- 2026-06-17: advisory: NVD publication date