apache-airflow-providers-smtp: No certificate validation on SMTP STARTTLS connections in SMTP provider
Apache Airflow's SMTP provider SmtpHook called Python's smtplib.SMTP.starttls() without an SSL context, so no certificate validation was performed on the TLS upgrade. A man-in-the-middle between the Airflow worker and the SMTP server could present a self-signed certificate, complete the STARTTLS upgrade, and capture the SMTP credentials sent during the subsequent login() call. Users are advised to upgrade to the apache-airflow-providers-smtp version that contains the fix.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | apache-airflow-providers-smtp | >= 2.0.0, < 3.0.0 | 3.0.0 |
References
- https://lists.apache.org/thread/gb202qy5r31bgdd3d51d7s5o1jh40kc4
- https://github.com/apache/airflow/pull/65346
- https://github.com/advisories/GHSA-x8mh-94wc-33gv
- https://nvd.nist.gov/vuln/detail/CVE-2026-41016
- https://github.com/apache/airflow
- https://github.com/pypa/advisory-database/tree/main/vulns/apache-airflow-providers-smtp/PYSEC-2026-24.yaml
- CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N- Weakness (CWE)
CWE-295- Platform
- Python (PyPI)
- Package
apache-airflow-providers-smtp- Disclosed
- 30.04.2026
- Updated
- 11.10.2026 15:17
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-24 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-x8mh-94wc-33gv - CC BY 4.0
Vulnerability history: apache-airflow-providers-smtp
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 2
- First → latest
- 08.2023 04.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Medium 2
Disclosures per year
- 2023: 1
- 2024: 0
- 2025: 0
- 2026: 1
-
apache-airflow-providers-smtp: No certificate validation on SMTP STARTTLS connections in SMTP provider this entry
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