CVE-2026-41016

Apache Airflow Providers SMTP: No certificate validation on SMTP STARTTLS connections in SMTP provider

Published Apr 30, 2026 CVSS 3.1 · 5.9 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-x8mh-94wc-33gv apache-airflow-providers-smtp: No certificate validation on SMTP STARTTLS connections in SMTP provider
History
Type Values Removed Values Added
First Time appeared Apache airflow
CPEs cpe:2.3:a:apache:airflow:*:*:*:*:*:*:*:*
Vendors & Products Apache airflow
Type Values Removed Values Added
First Time appeared Apache
Apache airflow Providers Smtp
Vendors & Products Apache
Apache airflow Providers Smtp
Type Values Removed Values Added
Metrics cvssV3_1

{'score': 5.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title Apache Airflow Providers SMTP: No certificate validation on SMTP STARTTLS connections in SMTP provider
Weaknesses CWE-295
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
apache
Published
Updated
Apr 30, 2026, 1:17 PM
Reserved
Apr 16, 2026, 2:38 AM
Status
Analyzed
Published
Apr 30, 2026, 10:16 AM
Modified
Oct 26, 2026, 9:10 PM