Apache Airflow FAB provider: the Authentik OAuth path in the FAB auth manager does not validate the issuer or audience claims of the idtoken it accepts. An attacker holding a token that the same Authentik identity provider minted for a different client application can present it to Airflow and be authenticated as the user it names, because the audience claim is never checked. Affects deployments using the FAB auth manager with Authentik OAuth where the same Authentik instance also serves other applications; the attacker needs a valid token for any of those other applications, not for Airflow.

CVE-2026-75156 corrected the same missing validation on the Azure AD path in this file; the Authentik path was left unchanged and is fixed here. Deployments that applied the CVE-2026-75156 fix and use Authentik must also upgrade for this one.

Users of apache-airflow-providers-fab are recommended to upgrade to version 3.9.0 or later, which fixes the issue.

The FAB auth manager's Azure AD OAuth login defaulted verifysignature=False when decoding the ID token, so an attacker able to present a forged or unsigned (alg:none) ID token to the OAuth callback could bypass authentication and log in as an arbitrary user, including one holding the Admin role (CWE-347). Deployments running the FAB auth manager with the Azure AD OAuth login path under its default configuration are affected; the Authentik path already defaulted to True. This issue affects apache-airflow-providers-fab before 3.7.3. Users are advised to upgrade to apache-airflow-providers-fab 3.7.3, which defaults verifysignature=True.

Apache Airflow FAB Auth Manager contains an LDAP filter injection vulnerability (CWE-90) that allows unauthenticated attackers to exfiltrate directory data or bypass authentication. Upgrade to apache-airflow-providers-fab 3.6.4 or later. If immediate upgrade is not possible, disable LDAP authentication until the provider can be updated.

Severity: Moderate

Affected versions:

- Apache Airflow FAB provider (apache-airflow-providers-fab) before 3.6.4

Description:

Apache Airflow FAB Auth Manager contains an LDAP filter injection vulnerability (CWE-90) that allows unauthenticated attackers to exfiltrate directory data or bypass authentication. Upgrade to apache-airflow-providers-fab 3.6.4 or later. If immediate upgrade is not possible, disable LDAP authentication until the provider can be updated.

Credit:

Venkatraman Kumar (r3dw0lfsec), Securin (finder) orbisai0security (automated scanner — Orbis Security AI) (remediation developer)

References:

https://github.com/apache/airflow/pull/66417 https://airflow.apache.org/ https://www.cve.org/CVERecord?id=CVE-2026-46745