How severe is CVE-2026-34538?

CVE-2026-34538 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-2026-34538 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-34538?

CVE-2026-34538 affects Apache Airflow. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-34538?

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

Does CVE-2026-34538 have an EU (EUVD) identifier?

Yes. CVE-2026-34538 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-20878.

When was CVE-2026-34538 published?

CVE-2026-34538 was published on 2026-04-09 and last updated on 2026-06-17.

CVE-2026-34538

CVE-2026-34538 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-668.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
EPSS exploit prediction: 1% (48th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-20878
Weakness: CWE-668
Affected product: Apache Airflow
Published: 2026-04-09
Last modified: 2026-06-17

Description

Apache Airflow versions 3.0.0 through 3.1.8 DagRun wait endpoint returns XCom result values even to users who only have DAG Run read permissions, such as the Viewer role.This behavior conflicts with the FAB RBAC model, which treats XCom as a separate protected resource, and with the security model documentation that defines the Viewer role as read-only. Airflow uses the FAB Auth Manager to manage access control on a per-resource basis. The Viewer role is intended to be read-only by default, and the security model documentation defines Viewer users as those who can inspect DAGs without accessing sensitive execution results. Users are recommended to upgrade to Apache Airflow 3.2.0 which resolves this issue.

Frequently asked questions

What is CVE-2026-34538?: Apache Airflow versions 3.0.0 through 3.1.8 DagRun wait endpoint returns XCom result values even to users who only have DAG Run read permissions, such as the Viewer role.This behavior conflicts with the FAB RBAC model, which treats XCom as a separate protected resource, and with the security model documentation that defines the Viewer role as read-only. Airflow uses the FAB Auth Manager to manage access control on a per-resource basis. The Viewer role is intended to be read-only by default, and the security model documentation defines Viewer users as those who can inspect DAGs without accessing sensitive execution results. Users are recommended to upgrade to Apache Airflow 3.2.0 which resolves this issue.
How severe is CVE-2026-34538?: CVE-2026-34538 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-2026-34538 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-34538?: CVE-2026-34538 affects Apache Airflow. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-34538?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-34538 have an EU (EUVD) identifier?: Yes. CVE-2026-34538 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-20878.
When was CVE-2026-34538 published?: CVE-2026-34538 was published on 2026-04-09 and last updated on 2026-06-17.

References

Affected products (1)

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

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