CVE-2026-49267

Apache Airflow: No certificate validation on SMTP STARTTLS connections

Published Jun 1, 2026 CVSS 3.1 · 5.9 Medium EPSS < 1% KEV · Not listed
Description
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-799x-qp47-8qwq Apache Airflow has no certificate validation on SMTP STARTTLS connections
History
Type Values Removed Values Added
CPEs cpe:2.3:a:apache:airflow:*:*:*:*:*:*:*:*
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 5.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N'}

Type Values Removed Values Added
First Time appeared Apache
Apache airflow
Vendors & Products Apache
Apache airflow
Type Values Removed Values Added
Description 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.
Title Apache Airflow: No certificate validation on SMTP STARTTLS connections
Weaknesses CWE-295
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
apache
Published
Updated
Nov 3, 2026, 6:57 AM
Reserved
May 28, 2026, 4:39 PM
Status
Analyzed
Published
Jun 1, 2026, 9:16 AM
Modified
Nov 3, 2026, 7:20 AM