Apache Airflows EmailOperator and the underlying airflow.utils.email helpers established SMTP STARTTLS connections without verifying the remote certificate when the deployment used [email] smtp_starttls=True without [email] smtp_ssl. An attacker positioned between the worker and the configured SMTP server (network MITM — typical hostile-network attack-surface for environments where the SMTP relay sits outside the workers trust boundary) could present a self-signed certificate, have the worker complete the STARTTLS handshake silently, and capture the SMTP AUTH credentials and message contents the worker forwarded.
This CVE covers the core apache-airflow side of the same root cause already covered for the SMTP provider by CVE-2026-41016 (published 2026-04-27, covering apache-airflow-providers-smtp). Users who already applied the SMTP-provider fix from CVE-2026-41016 should additionally upgrade apache-airflow to 3.2.2 or later to cover the core-side path through airflow.utils.email. Affects deployments configured with smtp_starttls=True and smtp_ssl=False where the SMTP relay is reachable across a less-trusted network segment than the worker.
Users are advised to upgrade to apache-airflow 3.2.2 or later.
Weakness
The product does not validate, or incorrectly validates, a certificate.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Airflow | Apache | 2.0.0 (including) | 3.2.2 (excluding) |