CVE-2026-41016 — 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-…
Published: 2026-04-30 · CVSS: 5.9 · CVSS 3.1
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7