Vulnerability in Apache Apache-Airflow-Providers-Fab
CVE-2026-59243
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`.
EPSS: 0.004 (37.5th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
Affected products
Weakness classification (CWE)
Public proof-of-concept exploits
References
- security@apache.org (Patch, patch)
- security@apache.org (vendor-advisory, Mailing List, Vendor Advisory)
- af854a3a-2127-422b-91ae-364da2661108 (Mailing List, Third Party Advisory)
Frequently asked questions
- What is CVE-2026-59243?
- CVE-2026-59243 is a critical-severity vulnerability in Apache Apache-Airflow-Providers-Fab, classified under Improper Verification of Cryptographic Signature. CVSS score: 9.8/10. Published 2026-07-29.
- How severe is CVE-2026-59243?
- Critical severity. CVSS v3 base score is 9.8 out of 10.
- Is CVE-2026-59243 known to be exploited?
- 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.