What is CVE-2026-75156?

CVE-2026-75156 is a critical-severity vulnerability in Apache Apache-Airflow-Providers-Fab, classified under Origin Validation Error. CVSS score: 9.1/10. Published 2026-09-08.

How severe is CVE-2026-75156?

Critical severity. CVSS v3 base score is 9.1 out of 10.

Vulnerability in Apache Apache-Airflow-Providers-Fab

CVE-2026-75156

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 · last modified 2026-09-18.

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.

EPSS exploit prediction

EPSS: 0.004 (30.8th percentile), scored 2026-10-25.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 31st percentile — 30.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000

Affected products

Weakness classification (CWE)

CWE-346 — Origin Validation Error

References

github.com/apache/airflow/pull/71735 (Patch, patch, Vendor Advisory)
lists.apache.org/thread/n3l6z4jfdxj4p0t8l7m6olkq6xsc6f76 (vendor-advisory, Mailing List)
www.cve.org/CVERecord (related, Third Party Advisory)

Frequently asked questions

What is CVE-2026-75156?: CVE-2026-75156 is a critical-severity vulnerability in Apache Apache-Airflow-Providers-Fab, classified under Origin Validation Error. CVSS score: 9.1/10. Published 2026-09-08.
How severe is CVE-2026-75156?: Critical severity. CVSS v3 base score is 9.1 out of 10.