Critical [CVE-2026-59243 +1] Apache Airflow FAB provider: FAB Azure AD OAuth: id_token issuer/audience not validated — cross-tenant authentication bypass
This critical-severity Apache Software Foundation advisory covers CVE-2026-75156 and CVE-2026-59243 affecting Apache Airflow FAB.
Aggregated and source-linked by VulniPulse. Data sources, validation and limitations. This bulletin covers 2 CVEs; its score, affected versions and guidance may apply to different issues within that bulletin.
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Summary
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.
- Apache Airflow FAB provider 3.7.3 before 3.8.1
Official advisory · high-confidence parse· fetched 2 months ago·verify at source
Mitigation checklist
- 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.
Official advisory · high-confidence parse· fetched 2 months ago·verify at source
More Apache Software Foundation advisories
- CVE-2026-86466Sep 16, 2026Apache Airflow FAB provider: the Authentik OAuth path in the FAB auth manager does not
- CVE-2026-82310Sep 16, 2026Apache Airflow FAB provider: deactivating a user account does not stop tokens issued
- CVE-2026-86462Sep 16, 2026Apache Airflow FAB provider: changing a user's password through the Admin user-edit PATCH
- CVE-2026-82311Sep 16, 2026Apache Airflow FAB provider: resetting a user's password does not delete that user's
- CVE-2026-59245Jul 13, 2026Apache Airflow FAB provider: FAB auth manager: a DAG named "DAGs" hijacks the global
- CVE-2026-111422Oct 26, 2026Apache Airflow SSH provider command injection
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