Apache-airflow-providers-fab Security Flaw CVE-2026-75156 Disclosed

Apache-airflow-providers-fab is affected by CVE-2026-75156, rated 9.1 (critical). No in-the-wild exploitation has been confirmed in the CISA KEV catalog at the time of writing.

What the flaw is

The NIST National Vulnerability Database describes it as follows:

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.

At a glance

What defenders should do

• Patch: apply the fixed release from Apache; check the vendor advisory linked below for the exact versions.
• Inventory: identify every instance of Apache-airflow-providers-fab, prioritising internet-facing ones.