CVE-2026-41016

MEDIUM5.9EPSS 0.02%

apache-airflow-providers-smtp: No certificate validation on SMTP STARTTLS connections in SMTP provider

Published: 4/30/2026Modified: 6/2/2026

Also known as:GHSA-x8mh-94wc-33gvCGA-7pfp-9chv-rwhhPYSEC-2026-24

Description

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.

Affected packages (2)

PyPI/apache-airflow-providers-smtp>= 2.0.0, < 3.0.0
PyPI/apache-airflow-providers-smtp>= 2.0.0, < 3.0.0

CVSS scores

Source	Version	Severity	Vector
osv	CVSS 3.1	MEDIUM5.9	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

References (5)

ADVISORYhttps://nvd.nist.gov/vuln/detail/CVE-2026-41016
PATCHhttps://github.com/apache/airflow
WEBhttps://github.com/apache/airflow/pull/65346
WEBhttps://github.com/pypa/advisory-database/tree/main/vulns/apache-airflow-providers-smtp/PYSEC-2026-24.yaml
WEBhttps://lists.apache.org/thread/gb202qy5r31bgdd3d51d7s5o1jh40kc4