Apache Airflow's 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 worker's 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.
CVSS Details
- CVSS 3.1 Base Score: 5.9
- CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N)
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