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 (CWE-347). Deployments running the FAB auth manager with the Azure AD OAuth login path under its default configuration are affected; the Authentik path already defaulted to True. This issue affects apache-airflow-providers-fab before 3.7.3. Users are advised to upgrade to apache-airflow-providers-fab 3.7.3, which defaults verifysignature=True.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
apache-airflow-providers-fabto a version that resolves this vulnerability.Fixed in 3.7.3 - Configuration
Under the Azure AD OAuth login path, enable JWT signature verification by setting verify_signature=True (default is verify_signature=False before apache-airflow-providers-fab 3.7.3).
Apache Airflow FAB provider - FAB auth manager (Azure AD OAuth) verify_signature = True
Event History
Frequently Asked Questions
What is the severity of CVE-2026-59243?
CVE-2026-59243 has a severity rating of critical with a CVSS score of 9.8.
How do I fix CVE-2026-59243?
To fix CVE-2026-59243, ensure that the `verify_signature` option is set to `True` when configuring Azure AD OAuth in the FAB auth manager.
What are the potential impacts of CVE-2026-59243?
The potential impacts of CVE-2026-59243 include unauthorized access and the ability for attackers to log in as arbitrary users, including admins.
Who is affected by CVE-2026-59243?
CVE-2026-59243 affects users of Apache Airflow utilizing the FAB provider for Azure AD OAuth.
What type of vulnerability is CVE-2026-59243?
CVE-2026-59243 is a security vulnerability related to authentication that allows for bypassing login mechanisms.