# CVE-2026-75156

## Summary

- **CVE ID:** CVE-2026-75156
- **Severity:** CRITICAL
- **CVSS Score:** 9.1 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N)
- **CWE:** CWE-346
- **Published:** Sep 8, 2026
- **Last Modified:** Sep 8, 2026

## Description

Apache Airflow FAB provider versions 3.7.3 through 3.8.0 do not validate the issuer or audience of Azure AD `id_token`s during OAuth login. Deployments are affected only when the FAB auth manager is configured with Azure AD as an OAuth provider. Because the signing keys are fetched from Microsoft's **multi-tenant** JWKS endpoint, an `id_token` minted in *any* Azure tenant — including one the attacker creates — passes signature verification, and the username and role assignments are then read from that attacker-controlled token. Anyone able to register an Azure tenant can therefore authenticate to the Airflow UI with no prior access to the deployment.

The fix for **CVE-2026-59243** was incomplete, and this advisory closes the remaining gap: that fix made the provider verify the `id_token` signature, but did not add issuer or audience checks. Operators who already applied the CVE-2026-59243 fix are **still affected and must upgrade again** — 3.7.3 is the release that shipped that fix, so every version containing it falls inside this affected range. Upgrade to apache-airflow-providers-fab `3.8.1` or later.

## Affected Products

- Apache Software Foundation — Apache Airflow FAB provider (3.7.3)

## References

- [CNA](https://github.com/apache/airflow/pull/71735)
- [CNA](https://lists.apache.org/thread/n3l6z4jfdxj4p0t8l7m6olkq6xsc6f76)
- [CNA](https://www.cve.org/CVERecord?id=CVE-2026-59243)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.18%
- **EPSS Percentile:** 8.0

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._