Vulnerability · Published Apr 30, 2026 · Assigned by apache
CVE-2026-41016Apache Airflow Providers SMTP: No certificate validation on SMTP STARTTLS connections in SMTP provider
Medium 5.9
In plain English
A medium-severity improper certificate validation in Apache Airflow Providers SMTP from Apache Software Foundation. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 19% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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 & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| PyPI | apache-airflow-providers-smtp | 3.0.0 | GHSA-x8mh-94wc-33gv |
| PyPI | apache-airflow-providers-smtp | 3.0.0 | PYSEC-2026-24 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Apache Software Foundation | Apache Airflow Providers SMTP | 2.0.0 – before 3.0.0 |
Weakness: CWE-295 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N