Vulnerability Description
The FAB auth manager's Azure AD OAuth login defaulted `verify_signature=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 `verify_signature=True`.
CVSS Score
CRITICAL
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Apache | Apache-Airflow-Providers-Fab | < 3.7.3 |
Related Weaknesses (CWE)
References
- https://github.com/apache/airflow/pull/69374Patch
- https://lists.apache.org/thread/x4784l7z00tl3gw4tv2dmvoon77rxgplMailing ListVendor Advisory
- http://www.openwall.com/lists/oss-security/2026/07/28/10Mailing ListThird Party Advisory
FAQ
What is CVE-2026-59243?
CVE-2026-59243 is a vulnerability with a CVSS score of 9.8 (CRITICAL). The FAB auth manager's Azure AD OAuth login defaulted `verify_signature=False` when decoding the ID token, so an attacker able to present a forged or unsigned (`alg:none`) ID token to the OAuth callba...
How severe is CVE-2026-59243?
CVE-2026-59243 has been rated CRITICAL with a CVSS base score of 9.8/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-59243?
Check the references section above for vendor advisories and patch information. Affected products include: Apache Apache-Airflow-Providers-Fab.