Apache Airflow Providers SMTP: No certificate validation on SMTP STARTTLS connections in SMTP provider
Apache Airflow's SMTP provider `SmtpHook` called Python's `smtplib.SMTP.starttls()` without an SSL context, so no certificate validation was performed on the TLS upgrade. A man-in-the-middle between the Airflow worker and the SMTP server could present a self-signed certificate, complete the STARTTLS upgrade, and capture the SMTP credentials sent during the subsequent `login()` call. Users are advised to upgrade to the `apache-airflow-providers-smtp` version that contains the fix.
Apache Airflow SMTP Provider, Apache Airflow IMAP Provider, Apache Airflow: SMTP/IMAP client components allowed MITM due to missing Certificate Validation
Apache Airflow SMTP Provider before 1.3.0, Apache Airflow IMAP Provider before 3.3.0, and Apache Airflow before 2.7.0 are affected by the Validation of OpenSSL Certificate vulnerability.
The default SSL context with SSL library did not check a server's X.509 certificate. Instead, the code accepted any certificate, which could result in the disclosure of mail server credentials or mail contents when the client connects to an attacker in a MITM position.
Users are strongly advised to upgrade to Apache Airflow version 2.7.0 or newer, Apache Airflow IMAP Provider version 3.3.0 or newer, and Apache Airflow SMTP Provider version 1.3.0 or newer t