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 `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`.
- Affected
- Apache Software Foundation · Apache Airflow FAB provider
- CVSS v3.1 CNA
- 9.8 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS
- 0.64% chance of exploitation in the next 30 days, 50th percentile
- Published
- 2026-07-29
- Updated
- 2026-09-16
Proof-of-concept exploits (1)
- 0xdak/CVE-2026-59243_exploit0★ · 2026-08-04
Security advisories
- https://lists.apache.org/thread/x4784l7z00tl3gw4tv2dmvoon77rxgpl
- http://www.openwall.com/lists/oss-security/2026/07/28/10
- apache/airflow/pull/69374