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.
Published: 2026-09-08
Score: n/a
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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History

Tue, 08 Sep 2026 17:00:00 +0000

Type Values Removed Values Added
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.
Title Apache Airflow FAB provider: FAB Azure AD OAuth: id_token issuer/audience not validated — cross-tenant authentication bypass
Weaknesses CWE-346
References

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cve-icon MITRE

Status: PUBLISHED

Assigner: apache

Published:

Updated: 2026-09-08T16:47:48.290Z

Reserved: 2026-08-17T18:58:02.812Z

Link: CVE-2026-75156

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-08T17:18:30.393

Modified: 2026-09-08T17:18:30.393

Link: CVE-2026-75156

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses