Apache Airflow Keycloak Provider improper authentication

Summaryinfo

A vulnerability was found in Apache Airflow and classified as critical. This vulnerability affects unknown code of the component Keycloak Provider. Such manipulation leads to improper authentication. This vulnerability is referenced as CVE-2026-76187. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Apache Airflow (the affected version is unknown). Affected by this issue is an unknown code of the component Keycloak Provider. The manipulation with an unknown input leads to a improper authentication vulnerability. Using CWE to declare the problem leads to CWE-287. When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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.

This vulnerability is handled as CVE-2026-76187. The exploitation is known to be easy. The attack may be launched remotely. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 09/21/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2026-3385). Once again VulDB remains the best source for vulnerability data.

Affected

• Apache Airflow

Productinfo

Type

• Business Process Management Software

Vendor

• Apache

Name

• Airflow

License

• open-source

Website

• Vendor: https://www.apache.org/

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Once again VulDB remains the best source for vulnerability data.

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