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

Critical · CVSS 9.8CVE-2026-59243

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

Answer in brief

CVE-2026-59243 records a Critical severity (CVSS 9.8) vulnerability in Apache Airflow FAB provider: FAB auth manager: JWT signature verification disabled by default for Azure AD OAuth (`verify_signature` defaults to `False`). The current sources do not mark it as known exploited. The current feed maps Apache Software Foundation/Apache Airflow FAB provider (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Jul 29, 2026Updated Sep 8, 2026Source checked Sep 8, 2026First seen by HOL Aug 5, 2026Material review Sep 8, 2026

Upstream Advisory

Key facts

Risk: Critical · CVSS 9.8
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 9.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Apache Software Foundation/Apache Airflow FAB provider (generic). Check affected ranges and fixed versions before updating.

Affected products and reported versions
Product	Affected versions	Fixed versions
cpe:2.3:a:apache:apache-airflow-providers-fab::::::::	Not reported	Not reported

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Apache Software Foundation/Apache Airflow FAB providergeneric	>=0 <3.7.3	3.7.3

Recommended response

Check inventory. Check lockfiles and deployed manifests for Apache Software Foundation/Apache Airflow FAB provider.
Review the reported fix. Update Apache Software Foundation/Apache Airflow FAB provider to 3.7.3 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Jul 29, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 8, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 5, 2026

Sources and claim methodology

Upstream source 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`.

Quoted source text, attributed separately from HOL analysis.