CVE-2026-76187
Received Received - Intake

Authentication Bypass in Apache Airflow Keycloak Provider

Publication date: 2026-09-16

Last updated on: 2026-09-16

Assigner: Apache Software Foundation

Description
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.

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Meta Information

Published
2026-09-16
Last Modified
2026-09-16
Generated
2026-09-16
AI Q&A
2026-09-16
EPSS Evaluated
N/A
NVD
CVE-2026-76187
EUVD
EUVD-2026-80324

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
apache airflow_providers_keycloak 0.10.0

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-287 When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.

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Executive Summary

This vulnerability affects Apache Airflow's Keycloak provider before version 0.10.0. It allows unauthenticated access to the token endpoint, which accepts client-credentials grants for any confidential client in the Keycloak realm, not just the one configured for Airflow. This means credentials from unrelated applications sharing the same realm can be used to log into Airflow, which then mints a session token for that application's service account.

Detection Guidance

Check Apache Airflow Keycloak provider version with pip show apache-airflow-providers-keycloak. If version is below 0.10.0, the system is vulnerable. Inspect Keycloak realm settings for shared confidential clients and verify token endpoint (/auth/token) access logs for unauthorized client-credentials grants.

Impact Analysis

An attacker with valid credentials for any client in a shared Keycloak realm can gain access to Airflow. The attacker can then obtain a signed session token for that client's service account, potentially accessing resources the service account is authorized to use. The impact depends on the privileges of the compromised service account.

Compliance Impact

This vulnerability could lead to unauthorized access to sensitive data, violating compliance requirements such as GDPR's data protection principles or HIPAA's access controls. Unauthorized access may result in data breaches, requiring breach notifications and potential fines under these regulations.

Mitigation Strategies

Upgrade apache-airflow-providers-keycloak to version 0.10.0 or later immediately. Review Keycloak realm configurations to ensure no unrelated confidential clients share the same realm with Airflow. Rotate all client secrets for clients in the shared realm as a precaution.

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