How severe is CVE-2021-38540?

CVE-2021-38540 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-38540 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 81% (100th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-38540?

CVE-2021-38540 affects Apache Airflow. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-38540?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-38540 published?

CVE-2021-38540 was published on 2021-09-09 and last updated on 2026-06-17.

CVE-2021-38540

CVE-2021-38540 is a critical-severity vulnerability in Apache Airflow with a CVSS 3.x base score of 9.8. Its EPSS exploit-prediction score of 81% places it in the 100th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-306.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 81% (100th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-306
Affected product: Apache Airflow
Published: 2021-09-09
Last modified: 2026-06-17

Description

The variable import endpoint was not protected by authentication in Airflow >=2.0.0, <2.1.3. This allowed unauthenticated users to hit that endpoint to add/modify Airflow variables used in DAGs, potentially resulting in a denial of service, information disclosure or remote code execution. This issue affects Apache Airflow >=2.0.0, <2.1.3.

Frequently asked questions

What is CVE-2021-38540?: The variable import endpoint was not protected by authentication in Airflow >=2.0.0, <2.1.3. This allowed unauthenticated users to hit that endpoint to add/modify Airflow variables used in DAGs, potentially resulting in a denial of service, information disclosure or remote code execution. This issue affects Apache Airflow >=2.0.0, <2.1.3.
How severe is CVE-2021-38540?: CVE-2021-38540 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-38540 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 81% (100th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-38540?: CVE-2021-38540 affects Apache Airflow. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-38540?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-38540 published?: CVE-2021-38540 was published on 2021-09-09 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:apache:airflow:*:*:*:*:*:*:*:*

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