# CVE-2026-49267: Apache Airflow: No certificate validation on SMTP STARTTLS connections

Status: published. Published: 2026-06-01. Updated: 2026-11-03.

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

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: apache) — https://github.com/apache/airflow/pull/65346

## Affected products and versions

- Apache Software Foundation / Apache Airflow (apache-airflow): ≥ 2.0.0; < 3.0.0 (affected, semver). Source: CNA: apache
- Apache Software Foundation / Apache Airflow (apache-airflow-core): ≥ 3.0.0; < 3.2.2 (affected, semver). Source: CNA: apache

## Severity and prioritization

- CVSS 3.1: 5.9 (medium); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N; source: ADP: CISA-ADP

- CISA KEV: No listing in collected sources

- EPSS: 0.18% as of 2026-11-02; percentile 8.09%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-295

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/apache/airflow/pull/65346 (CNA: apache; patch)

- https://lists.apache.org/thread/6v2ds757000msmjmovnnqryqzks83ps0 (CNA: apache; vendor-advisory)

## Provenance

- CNA: apache: https://www.cve.org/CVERecord?id=CVE-2026-49267; retrieved 2026-11-03; source updated 2026-11-03

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-49267; retrieved 2026-11-03; source updated Not reported

Revision: b114f042d6106af6691f66173c8d3972328904db13838c9fef529c643393fb3b

Canonical: https://y2.dev/cve/CVE-2026-49267

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