Vulnerability in Apache Airflow
CVE-2026-41016
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.
Vulnerability class: Improper Certificate Validation
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N.
EPSS exploit prediction
EPSS: 0.003 (17.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 17th percentile — 17.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000
Affected products
- Apache Airflow
- Apache Software Foundation Airflow Providers Smtp — versions 2.0.0
Weakness classification (CWE)
References
- github.com/apache/airflow/pull/65346 (Patch, patch, Issue Tracking)
- lists.apache.org/thread/gb202qy5r31bgdd3d51d7s5o1jh40kc4 (vendor-advisory, Mailing List, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-41016?
- CVE-2026-41016 is a medium-severity vulnerability in Apache Airflow, classified under Improper Certificate Validation. CVSS score: 5.9/10. Published 2026-04-30.
- How severe is CVE-2026-41016?
- Medium severity. CVSS v3 base score is 5.9 out of 10.