Apache Airflow FAB provider: FAB auth manager: JWT signature verification disabled by default for Azure AD OAuth (`verify_signature` defaults to `False`)
Title source: cnaExploitation Summary
EIP tracks 2 public exploits for CVE-2026-59243. PoCs published by 0xdak, MalHyuk.
AI-analyzed exploit summary Exploits an OAuth signature verification flaw (CWE-347) in Apache Airflow's FAB provider, allowing unauthenticated attackers to bypass authentication by forging Azure OAuth tokens with admin roles. Achieves RCE by triggering a pre-seeded DAG with a BashOperator executing attacker-controlled commands.
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`.
Exploits (2)
Exploits an OAuth signature verification flaw (CWE-347) in Apache Airflow's FAB provider, allowing unauthenticated attackers to bypass authentication by forging Azure OAuth tokens with admin roles. Achieves RCE by triggering a pre-seeded DAG with a BashOperator executing attacker-controlled commands.
This repository contains a functional proof-of-concept exploit for CVE-2026-59243, a JWT signature verification bypass in Apache Airflow's FAB Auth Manager. The exploit forges unsigned JWT tokens to bypass authentication and gain Admin privileges by exploiting the `verify_signature=False` default in Azure AD OAuth integration.
References (3)
Scores
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H