CVE-2026-94135: Apache Airflow SFTP provider: Async SFTP hook disables host-key verification by default

[Jarek Potiuk <potiuk () apache org>]

Severity: moderate 

Affected versions:

- Apache Airflow SFTP provider before 7.0.0

Description:

The Apache Airflow SFTP provider's deferrable code paths (`SFTPTrigger`, `SFTPHookAsync`, `SFTPClientPool`) disable SSH 
host-key verification by default unless the connection explicitly sets `no_host_key_check` to false. Deployments that 
run SFTP sensors or operators in deferrable mode are affected. An attacker in a machine-in-the-middle position between 
the triggerer and the SFTP server can impersonate the server and capture the credentials or data exchanged.

Users of apache-airflow-providers-sftp are recommended to upgrade to apache-airflow-providers-sftp 7.0.0 or later. This 
is a separate defect from CVE-2026-94134 (the synchronous SSH hook default, which also affects the SFTP hook); users 
who applied the fix for one also need this release for the other - apache-airflow-providers-sftp 7.0.0 fixes both.

Credit:

Claude Security Scans (tool)
Igor Stepansky, OX Security (finder)
Jarek Potiuk (remediation developer)

References:

https://github.com/apache/airflow/pull/73419
https://www.cve.org/CVERecord?id=CVE-2026-94134
https://airflow.apache.org/
https://www.cve.org/CVERecord?id=CVE-2026-94135