The vulnerability arises because the async SFTP hook in the Airflow SFTP provider turns off SSH host‑key verification by default in deferrable code paths such as SFTPTrigger, SFTPHookAsync, and SFTPClientPool, a weakness identified as CWE‑322. When host‑key checks are bypassed, an attacker positioned between the Airflow triggerer and the target SFTP server can impersonate the server and intercept credentials or data transmitted during the session. This leads to a clear risk of credential theft and data compromise.

All deployments of apache‑airflow‑providers‑sftp using any version dated before the release of 7.0.0 that run SFTP sensors or operators in deferrable mode are affected. The danger exists regardless of the specific Airflow instance version, as the default host‑key check behavior is hard‑coded in the provider’s asynchronous implementation.

The EPSS score is < 1% and it is not listed in the CISA KEV catalog, but the potential for exploitation remains high because it requires only a man‑in‑the‑middle position and no special credentials. The CVSS score is 4.3, indicating a moderate severity, yet the vulnerability still permits attackers to capture authentication information and sensitive file contents, which is a serious security concern.