How severe is CVE-2021-26559?

CVE-2021-26559 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2021-26559 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (85th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-26559?

CVE-2021-26559 affects Apache Airflow. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-26559?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-26559 published?

CVE-2021-26559 was published on 2021-02-17 and last updated on 2026-06-17.

CVE-2021-26559

CVE-2021-26559 is a medium-severity vulnerability in Apache Airflow with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-284.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 4.0
EPSS exploit prediction: 3% (85th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-284
Affected product: Apache Airflow
Published: 2021-02-17
Last modified: 2026-06-17

Description

Improper Access Control on Configurations Endpoint for the Stable API of Apache Airflow allows users with Viewer or User role to get Airflow Configurations including sensitive information even when `[webserver] expose_config` is set to `False` in `airflow.cfg`. This allowed a privilege escalation attack. This issue affects Apache Airflow 2.0.0.

Frequently asked questions

What is CVE-2021-26559?: Improper Access Control on Configurations Endpoint for the Stable API of Apache Airflow allows users with Viewer or User role to get Airflow Configurations including sensitive information even when `[webserver] expose_config` is set to `False` in `airflow.cfg`. This allowed a privilege escalation attack. This issue affects Apache Airflow 2.0.0.
How severe is CVE-2021-26559?: CVE-2021-26559 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2021-26559 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (85th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-26559?: CVE-2021-26559 affects Apache Airflow. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-26559?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-26559 published?: CVE-2021-26559 was published on 2021-02-17 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:apache:airflow:2.0.0:*:*:*:*:*:*:*

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