Apache Airflow Keycloak Provider session fixiation

Summaryinfo

A vulnerability was found in Apache Airflow. It has been rated as critical. The affected element is an unknown function of the component Keycloak Provider. The manipulation leads to session fixiation. This vulnerability is listed as CVE-2026-76186. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability was found in Apache Airflow (version unknown) and classified as critical. This issue affects an unknown function of the component Keycloak Provider. The manipulation with an unknown input leads to a session fixiation vulnerability. Using CWE to declare the problem leads to CWE-384. Authenticating a user, or otherwise establishing a new user session, without invalidating any existing session identifier gives an attacker the opportunity to steal authenticated sessions. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

Apache Airflow Keycloak provider: from Airflow 3.3 the Keycloak auth manager takes a user's identity from the signed Airflow session token but takes the Keycloak access and refresh tokens used for every authorization decision from separate, unauthenticated cookies, and never checks that the two describe the same subject. A user who holds any valid Airflow login of their own, together with another subject's Keycloak access or refresh token obtained out of band, can pair the two: Airflow then authorizes requests with the foreign token's privileges while the session identity, audit log and cache keys continue to name the attacker's own account. The refresh path re-issues an Airflow session token for the original identity carrying the foreign tokens, so the mismatched pairing survives across sessions. Affects deployments running Airflow 3.3 or later with the Keycloak auth manager. Earlier versions carried the Keycloak tokens inside the signed session token, so the binding existed and was lost when they moved into separate cookies. Users of apache-airflow-providers-keycloak are recommended to upgrade to version 0.10.0 or later, which binds the cookie-supplied tokens to the session identity.

The identification of this vulnerability is CVE-2026-76186. The exploitation is known to be easy. The attack may be initiated remotely. It demands that the victim is doing some kind of user interaction. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $5k-$25k at the moment (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). Be aware that VulDB is the high quality 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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Be aware that VulDB is the high quality source for vulnerability data.

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