Apache Airflow: No certificate validation on SMTP STARTTLS connections

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Summary

CVECVE-2026-49267
StatePUBLISHED
Assignerapache
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-06-01 09:16:20 UTC
Updated2026-06-03 02:06:28 UTC
DescriptionApache 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.

Risk And Classification

Primary CVSS: v3.1 5.9 MEDIUM from ADP

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS: 0.000620000 probability, percentile 0.194380000 (date 2026-06-08)

Problem Types: CWE-295 | CWE-295 CWE-295: Improper Certificate Validation

VersionSourceTypeScoreSeverityVector
3.1ADPDECLARED5.9MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
3.1134c704f-9b21-4f2e-91b3-4a467353bcc0Secondary5.9MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Apache Airflow All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Apache Software Foundation Apache Airflow affected 2.0.0 3.2.2 semver Not specified

References

ReferenceSourceLinkTags
github.com/apache/airflow/pull/65346 [email protected] github.com Issue Tracking, Patch
lists.apache.org/thread/6v2ds757000msmjmovnnqryqzks83ps0 [email protected] lists.apache.org Mailing List, Vendor Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Francis Bergin (@francisbergin) (en)

CNA: Jarek Potiuk (en)

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