NVD / CVE Program· CNA apache

CVE-2023-39441: Apache Airflow SMTP Provider, Apache Airflow IMAP Provider, Apache Airflow: SMTP/IMAP client components allowed MITM due to missing Certificate Validation

Noroxi assessment

Priority: Monitor (action score 23/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.80% (FIRST EPSS); higher than 56.6% of all records.
Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. Special conditions such as timing or configuration are required.
Fixed version: Apache Software Foundation Apache Airflow 2.7.0; Apache Software Foundation Apache Airflow IMAP Provider 3.3.0; Apache Software Foundation Apache Airflow SMTP Provider 1.30.
Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Apache Software Foundation Apache Airflow 2.7.0; Apache Software Foundation Apache Airflow IMAP Provider 3.3.0; Apache Software Foundation Apache Airflow SMTP Provider 1.30 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Apache Airflow SMTP Provider before 1.3.0, Apache Airflow IMAP Provider before 3.3.0, and Apache Airflow before 2.7.0 are affected by the Validation of OpenSSL Certificate vulnerability. The default SSL context with SSL library did not check a server's X.509 certificate. Instead, the code accepted any certificate, which could result in the disclosure of mail server credentials or mail contents when the client connects to an attacker in a MITM position. Users are strongly advised to upgrade to Apache Airflow version 2.7.0 or newer, Apache Airflow IMAP Provider version 3.3.0 or newer, and Apache Airflow SMTP Provider version 1.3.0 or newer to mitigate the risk associated with this vulnerability

MediumCVSS 5.9 · v3.1—No exploit Fix available

Published: Aug 23, 2023
Updated: Jun 17, 2026
EPSS: 0.8% · 56th percentile
CWE: CWE-295

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 23 / 40 · 5.9 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.8%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
apache	airflow	cpe:2.3:a:apache:airflow
apache	apache-airflow-providers-imap	cpe:2.3:a:apache:apache-airflow-providers-imap
apache	apache-airflow-providers-smtp	cpe:2.3:a:apache:apache-airflow-providers-smtp

Check your site's encryption

This vulnerability is about certificate validation or weak cryptography. The free SSL checker tests your certificate, enabled TLS versions and weak ciphers.

Run the SSL check

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

apache airflowbefore 2.7.0
apache apache-airflow-providers-imapbefore 3.3.0
apache apache-airflow-providers-smtpbefore 1.3.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (apache). Independent of NVD's CPE analysis and usually ahead of it.

Apache Software Foundation Apache Airflow
- before 2.7.0affected · semver
Apache Software Foundation Apache Airflow IMAP Provider
- before 3.3.0affected · semver
Apache Software Foundation Apache Airflow SMTP Provider
- before 1.30affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
PyPI	apache-airflow	before 2.7.0	2.7.0
PyPI	apache-airflow-providers-imap	before 3.3.0	3.3.0
PyPI	apache-airflow-providers-smtp	before 1.3.0	1.3.0

Same product

apache: all records

Other highest-scoring records for the same primary product.

CVE-2020-13927The previous default setting for Airflow's Experimental API was to allow all API requests without authentication, but this poses security riKEV
99Now
CVE-2020-11978An issue was found in Apache Airflow versions 1.10.10 and below.KEV
95Now
CVE-2021-38540Apache Airflow: Variable Import endpoint missed authentication check
63This week

Published before and after this one in the same product

← EarlierCVE-2023-39508Aug 5, 2023 · Apache Airflow: Airflow "Run task" feature allows execution with unnecessary priviledges
36Monitor
← EarlierCVE-2023-37379Aug 23, 2023 · Apache Airflow: Exposure of sensitive connection information, DOS and SSRF on "test connection" feature
33Monitor
Later →CVE-2023-40273Aug 23, 2023 · Session fixation in Apache Airflow web interface
33Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
Apache Software Foundation Apache Airflow	2.7.0	Vendor (CNA)
Apache Software Foundation Apache Airflow IMAP Provider	3.3.0	Vendor (CNA)
Apache Software Foundation Apache Airflow SMTP Provider	1.30	Vendor (CNA)
PyPI:apache-airflow	2.7.0	Package registry (OSV)
PyPI:apache-airflow-providers-imap	3.3.0	Package registry (OSV)
PyPI:apache-airflow-providers-smtp	1.3.0	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Martin Schobert, Pentagrid AGfinder

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

TR-23-0482 · Aug 24, 2023(Apache Airflow Güvenlik Zafiyeti)

All national notices →

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
No account or password is required.
No user action is required.
Special conditions such as timing or configuration are required.

If successful

Confidentiality: high · data can be read
Integrity: none
Availability: none

Attack vector: Network
Attack complexity: High
Privileges required: None
User interaction: None
Scope: Unchanged
Confidentiality impact: High
Integrity impact: None
Availability impact: None

Weakness class (CWE)

CWE-295 · Improper Certificate Validation

CVSS vector

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

nvd-primary

Root cause

A certificate validation error is silently swallowed instead of terminating the connection. Often, code added for a test environment makes its way into production.

The bug in code

The whole CWE-295 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

kotlin

1override fun checkServerTrusted(chain: Array<X509Certificate>, type: String) {
2  // Left empty for the test environment
3}

Fixed

kotlin

1val client = OkHttpClient.Builder()
2  .certificatePinner(
3    CertificatePinner.Builder()
4      .add("api.sirius.example", "sha256/…")
5      .build()
6  ).build()

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

—

Change log

Fix✗ → ✓Sep 28, 2026, 10:09 PM UTC

For records you follow, these changes also arrive as notifications. →

References

www.openwall.com/lists/oss-security/2023/08/23/2

Show all references (4 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records