CVE-2026-41016 | 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.

Published: 2026-04-30 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-41016 is rated Low Risk (30/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.27%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-41016

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-23 0.23% 0.27% +0.04%
2 2026-06-15 0.02% 0.23% +0.21%
3 2026-05-22 — 0.02% —

Full EPSS history (5 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-41016

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.9 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 2.2 3.6 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2026-41016

GitHub Security Advisory for CVE-2026-41016

GHSA-x8mh-94wc-33gv · Severity: medium · Ecosystem: pip — apache-airflow-providers-smtp: No certificate validation on SMTP STARTTLS connections in SMTP provider

Affected software / configurations for CVE-2026-41016

Vendor Product Version Raw CPE
apache airflow >= 2.0.0, < 3.0.0 cpe:2.3:a:apache:airflow:*:*:*:*:*:*:*:*

References for CVE-2026-41016

cvelogic Threat Intelligence