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.
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-41016US | — | — | ||
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-… | ||||
references
External citations — patches, advisories, analysis.
- https://github.com/apache/airflowPACKAGE
- https://github.com/apache/airflow/pull/65346WEB
- https://github.com/pypa/advisory-database/tree/main/vulns/apache-airflow-providers-smtp/PYSEC-2026-24.yamlWEB
- https://lists.apache.org/thread/gb202qy5r31bgdd3d51d7s5o1jh40kc4WEB
- https://nvd.nist.gov/vuln/detail/CVE-2026-41016ADVISORY
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