CVE-2026-49267: Apache Airflow: No certificate validation on SMTP STARTTLS connections
This Apache advisory covers CVE-2026-49267 in Apache Airflow.
- CVE-2026-49267
Key facts
- CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N· base score 5.9, scored by CISA-ADPAttack vector: network. Attack complexity: high. Privileges required: none. User interaction: none. Scope: unchanged. Confidentiality impact: high. Integrity impact: none. Availability impact: none.- Weakness
- CWE-295: Improper Certificate Validation
- CISA SSVC
- Exploitation: none observed. Automatable: no. Technical impact: partial. CISA, .
- CISA KEV
- Not listed (catalogue checked )
- Affected
- Apache Airflow 2.0.0 before 3.0.0; Apache Airflow 3.0.0 before 3.2.2
- Fixed in
- 3.0.0, 3.2.2
- Source published
- Source revised
- Listed by VulniPulse
Compiled by VulniPulse from the linked sources. How records are collected and checked.
Affected products & platforms
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.
Text from the source record.
- Apache Airflow 2.0.0 before 3.0.0
- Apache Airflow 3.0.0 before 3.2.2
Official advisory · medium-confidence parse· fetched ·verify at source
How to fix CVE-2026-49267
Upgrade to a fixed release named by Apache:
- 3.0.0
- 3.2.2
Vendor guidance
- 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`.
- Users are advised to upgrade to `apache-airflow` 3.2.2 or later.
Support dates for the fixed release lines
- Apache Airflow 3.0: support ended
- Apache Airflow 3.2: support ended
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Apache Software Foundation advisories, June 2026All Apache Software Foundation advisories
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