CVE-2026-49267
Apache Airflow: No certificate validation on SMTP STARTTLS connections
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.
INFO
Published Date :
June 1, 2026, 9:16 a.m.
Last Modified :
July 21, 2026, 7:10 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
Solution
- Upgrade Apache Airflow to version 3.2.2 or later.
- Ensure SMTP STARTTLS connections verify remote certificates.
- Configure SMTP with smtp_ssl=True if possible.
- Deploy SMTP relay within a trusted network boundary.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-49267.
| URL | Resource |
|---|---|
| https://github.com/apache/airflow/pull/65346 | Issue Tracking Patch |
| https://lists.apache.org/thread/6v2ds757000msmjmovnnqryqzks83ps0 | Mailing List Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-49267 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-49267
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-49267 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-49267 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Jul. 21, 2026
Action Type Old Value New Value Added Translation Title: Apache Airflow de Apache Software Foundation, Description: El EmailOperator de Apache Airflow y las funciones auxiliares subyacentes 'airflow.utils.email' establecían conexiones SMTP STARTTLS sin verificar el certificado remoto cuando la implementación utilizaba '[email] smtp_starttls=True' sin '[email] smtp_ssl'. Un atacante posicionado entre el worker y el servidor SMTP configurado (MitM de red - superficie de ataque típica de red hostil para entornos donde el relé SMTP se encuentra fuera del límite de confianza del worker) podría presentar un certificado autofirmado, hacer que el worker completara el handshake STARTTLS silenciosamente, y capturar las credenciales SMTP AUTH y el contenido del mensaje que el worker reenviaba. Este CVE cubre el lado central de apache-airflow de la misma causa raíz ya cubierta para el proveedor SMTP por 'CVE-2026-41016' (publicado el 27-04-2026, cubriendo 'apache-airflow-providers-smtp'). Los usuarios que ya aplicaron la corrección del proveedor SMTP de CVE-2026-41016 deberían actualizar adicionalmente 'apache-airflow' a 3.2.2 o posterior para cubrir la ruta del lado central a través de 'airflow.utils.email'. Afecta a las implementaciones configuradas con 'smtp_starttls=True' y 'smtp_ssl=False' donde el relé SMTP es accesible a través de un segmento de red menos confiable que el worker. Se aconseja a los usuarios actualizar a 'apache-airflow' 3.2.2 o posterior. -
CVE Modified by [email protected]
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'Apache Software Foundation', 'product': 'Apache Airflow', 'versions': [{'status': 'affected', 'version': '2.0.0', 'lessThan': '3.2.2', 'versionType': 'semver'}], 'packageName': 'apache-airflow', 'collectionURL': 'https://pypi.python.org', 'defaultStatus': 'unaffected'}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-49267', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-02T16:20:50.236710Z'} -
Initial Analysis by [email protected]
Jun. 03, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:apache:airflow:*:*:*:*:*:*:*:* versions from (including) 2.0.0 up to (excluding) 3.2.2 Added Reference Type Apache Software Foundation: https://github.com/apache/airflow/pull/65346 Types: Issue Tracking, Patch Added Reference Type Apache Software Foundation: https://lists.apache.org/thread/6v2ds757000msmjmovnnqryqzks83ps0 Types: Mailing List, Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 02, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N -
New CVE Received by [email protected]
Jun. 01, 2026
Action Type Old Value New Value 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. Added CWE CWE-295 Added Reference https://github.com/apache/airflow/pull/65346 Added Reference https://lists.apache.org/thread/6v2ds757000msmjmovnnqryqzks83ps0