# CVE-2026-75156: Apache Airflow FAB provider auth bypass in Azure AD OAuth

Source: https://junglewise.ai/threats/cve-2026-75156-apache-airflow-fab-provider-auth-bypass-in-azure-ad-oauth  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-08. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-75156 · Severity: critical · CVSS 9.1 · Published 2026-09-08

Apache Airflow's FAB authentication manager, when configured for Azure AD single sign-on (SSO), fails to verify that OAuth tokens were issued for your organization and application. An attacker can create a free Azure tenant, mint a valid token, and use it to log into your Airflow UI as any user. This bypasses all organizational access controls and authentication, allowing unauthorized actors to potentially modify workflows, access sensitive data, and disrupt operations.

Technologies: [Apache-Airflow-Providers-Fab](https://junglewise.ai/threats/technologies/apache-airflow-providers-fab). Vendors: [Apache](https://junglewise.ai/threats/vendors/apache).

## Quick answers

**Is CVE-2026-75156 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-75156 being exploited in the wild.

**How severe is CVE-2026-75156?** Critical severity, with a CVSS score of 9.1, published 8 September 2026.

**Which products and versions are affected?** Apache Airflow FAB provider 3.7.3 through 3.8.0.

**Is there a fix for CVE-2026-75156?** A patch was published on 2026-09-08: Fix available in apache-airflow-providers-fab 3.8.1 or later Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-75156 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-75156?** Check whether you run Apache-Airflow-Providers-Fab. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The FAB provider accepts Azure AD `id_token`s during OAuth login but fails to validate the issuer (`iss`) and audience (`aud`) claims. Although signature verification against Microsoft's multi-tenant JWKS endpoint is performed, the underlying authlib `decode()` call passes no `claims_options`, leaving issuer and audience validation unenforced. Because the JWKS endpoint (`login.microsoftonline.com/common/discovery/keys`) serves keys for all Azure tenants, an attacker can mint a valid, properly-signed token from any Azure tenant—including one they create—and the authentication will succeed. The username and role assignments are read directly from the attacker-controlled token payload. Affected versions 3.7.3–3.8.0 must upgrade to 3.8.1 or later; patches enforce both issuer matching the configured tenant and audience matching the application's client ID.

## Affected products

- Apache Airflow FAB provider 3.7.3 through 3.8.0

## Timeline

- 2026-09-08: disclosed: CVE-2026-75156 published
- 2026-09-08: patched: Fix available in apache-airflow-providers-fab 3.8.1 or later

## References

- [https://pypi.python.org/](https://pypi.python.org/)
- [https://github.com/apache/airflow/pull/71735](https://github.com/apache/airflow/pull/71735)

## Related threats

- [Apache Airflow FAB provider authentication bypass in Authentik OAuth](https://junglewise.ai/threats/cve-2026-86466-apache-airflow-fab-provider-authentication-bypass-in-authentik)
- [Apache Airflow FAB provider token revocation bypass for deactivated accounts](https://junglewise.ai/threats/cve-2026-82310-apache-airflow-fab-provider-token-revocation-bypass-for)
- [Apache Airflow FAB provider session invalidation bypass on password change](https://junglewise.ai/threats/cve-2026-86462-apache-airflow-fab-provider-session-invalidation-bypass-on)
- [Apache Airflow FAB provider session invalidation bypass](https://junglewise.ai/threats/cve-2026-82311-apache-airflow-fab-provider-session-invalidation-bypass)