NVD / CVE Program· CNA apache

CVE-2021-26697: Apache Airflow: Lineage API endpoint for Experimental API missed authentication check

Noroxi assessment

Priority: Monitor (action score 22/100)

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: 4.5% (FIRST EPSS); higher than 91.5% 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. No special conditions are required; it is repeatable.
Fixed version: apache-airflow (PyPI) 2.0.1rc1, 2.0.1.

Low priority for now. Upgrade to apache-airflow (PyPI) 2.0.1rc1, 2.0.1 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

The lineage endpoint of the deprecated Experimental API was not protected by authentication in Airflow 2.0.0. This allowed unauthenticated users to hit that endpoint. This is low-severity issue as the attacker needs to be aware of certain parameters to pass to that endpoint and even after can just get some metadata about a DAG and a Task. This issue affects Apache Airflow 2.0.0.

MediumCVSS 5.3 · v3.1—No exploit Fix available

Pre-auth

Published: Feb 17, 2021
Updated: Jun 16, 2026
EPSS: 4.5% · 91th percentile
CWE: CWE-269

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 21 / 40 · 5.3 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 1 / 30 · 4.5%

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

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Noroxi analysis

What does it mean in your environment?

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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

Affected versions

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

apache airflow2.0.0

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
- Apache Airflow 2.0.0affected

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	from 2.0.0 · before 2.0.1rc1	2.0.1rc1
PyPI	apache-airflow	before 2.0.1	2.0.1

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-2020-17526Dec 21, 2020 · Incorrect Session Validation in Apache Airflow Webserver versions prior to 1.10.14 with default config allows a malicious airflow user on si
37Monitor
← EarlierCVE-2021-26559Feb 17, 2021 · CWE-284 Improper Access Control on Configurations Endpoint for the Stable API
27Monitor
Later →CVE-2021-28359May 2, 2021 · Apache Airflow Reflected XSS via Origin Query Argument in URL
28Monitor

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
PyPI:apache-airflow	2.0.1	Package registry (OSV)
PyPI:apache-airflow	2.0.1rc1	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.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

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

No commit or PR link among the references.

Credits

All researchers

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

Ian Carroll

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).

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.
No special conditions are required; it is repeatable.

If successful

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

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

Weakness class (CWE)

CWE-269 · Improper Privilege Management

CVSS vector

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

nvd-primary

Root cause

To simplify setup, a service account is granted broad, cluster-wide permissions. The principle of least privilege is skipped during installation.

The bug in code

The whole CWE-269 class

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

Vulnerable

yaml

1kind: ClusterRole
2rules:
3  - apiGroups: ["*"]
4    resources: ["*"]
5    verbs: ["*"]

Fixed

yaml

1kind: Role
2metadata:
3  namespace: lodos-system
4rules:
5  - apiGroups: ["apps"]
6    resources: ["deployments"]
7    verbs: ["get", "list", "update"]

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

Abuse Elevation Control MechanismT1548

Change log

Fix✗ → ✓Sep 28, 2026, 10:45 PM UTC

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References

www.openwall.com/lists/oss-security/2021/02/17/2

Show all references (3 more)

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

All records