CVE-2026-59243 Apache Airflow FAB provider: FAB auth manager: JWT signature verification disabled by default for Azure AD OAuth (`verify_signature` defaults to `False`)

The FAB auth manager's Azure AD OAuth login defaulted verifysignature=False when decoding the ID token, so an attacker able to present a forged or unsigned alg:none ID token to the OAuth callback could bypass authentication and log in as an arbitrary user, including one holding the Admin role...