CVE-2026-76187

published 2026-09-16

CVE-2026-76187: Apache Airflow Keycloak provider: the unauthenticated token endpoint accepts a client-credentials grant for any confidential client registered in the Keycloak…

Priority P2 67 critical 9.8 CVSS 3.1

AV N AC L PR N UI N S U C H I H A H

Apache Airflow Keycloak provider: the unauthenticated token endpoint accepts a client-credentials grant for any confidential client registered in the Keycloak realm, not only the client configured for Airflow. No allowlist restricts which client ids may authenticate, so the credentials of an unrelated application that happens to share the realm are valid Airflow login credentials, and Airflow mints a signed session token for that application's service account. The endpoint also answers unauthenticated credential guesses against Keycloak under Airflow's identity.

Affects deployments using the Keycloak auth manager whose realm is shared with other confidential clients. The attacker needs valid credentials for any one of those clients, not for Airflow. Resource authorization is still evaluated per subject, so the access gained is whatever that service account holds, plus any endpoint gated only on being authenticated.

Users of apache-airflow-providers-keycloak are recommended to upgrade to version 0.10.0 or later, which accepts only the configured client on that grant.

Affected

2 ranges

Vendor	Product	Version range	Fixed in
apache	apache-airflow-providers-keycloak	< 0.10.0	0.10.0
apache_software_foundation	apache_airflow_keycloak_provider	< 0.10.0	0.10.0

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CWE-287