CVE-2021-38540Network attack vector

Unauthenticated DAG variable modification via unguarded import route

Published Sep 9, 2021 · Updated Aug 4, 2024

Authentication bypass in Apache Airflow 2.0.0 through 2.1.2 allows remote attackers to modify DAG variables through a web request. The VariableModelView.varimport POST route executes variable import without the create-variable access check. Any client that can reach the webserver can overwrite variables consumed by DAGs, enabling data disclosure, service interruption, or code execution when affected workflows use those values.

CVSS severity9.3
Critical
EPSS probability80.94%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in Apache Airflow 2.0.0 through 2.1.2 allows remote attackers to modify DAG variables through a web request. The VariableModelView.varimport POST route executes variable import without the create-variable access check. Any client that can reach the webserver can overwrite variables consumed by DAGs, enabling data disclosure, service interruption, or code execution when affected workflows use those values.

The record

CVE
CVE-2021-38540
Published
Sep 9, 2021
Updated
Aug 4, 2024
Vendor
The Apache Software Foundation
Product
Apache Airflow
Classifications
CWE-306, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 9, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=Apache Airflow <2.1.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache Airflowversion=Apache Airflow <2.1.3

Published CVSS scores

9.3GitHub Advisory DatabaseCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-306Missing Authentication for Critical Function
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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