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.
References
francisbergin Analyst
Apache Airflow's EmailOperator and the underlying
airflow.utils.emailhelpers established SMTP STARTTLS connections without verifying the remote certificate when the deployment used[email] smtp_starttls=Truewithout[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, coveringapache-airflow-providers-smtp). Users who already applied the SMTP-provider fix from CVE-2026-41016 should additionally upgradeapache-airflowto 3.2.2 or later to cover the core-side path throughairflow.utils.email. Affects deployments configured withsmtp_starttls=Trueandsmtp_ssl=Falsewhere the SMTP relay is reachable across a less-trusted network segment than the worker.Users are advised to upgrade to
apache-airflow3.2.2 or later.References