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Apache Airflow Providers FabWeb server / proxy · Apache

CVE-2026-59243

CRITICAL · 9.8 CVSS v3.1 Published 2026-07-29
Fix available
A fix is available. Upgrade to 3.7.3 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click 3 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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`.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The FAB auth manager's Azure AD OAuth login had a critical security misconfiguration where it defaulted verify_signature=False when decoding ID tokens. This allowed attackers to bypass authentication entirely by presenting forged or unsigned (alg:none) ID tokens to the OAuth callback, enabling privilege escalation to Admin or any other user account.

MitigationUpgrade apache-airflow-providers-fab to version 3.7.3 or later immediately, as this version sets verify_signature=True by default. Prior to upgrade, confirm no other authentication bypasses exist and review Azure AD OAuth configuration.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Apache Airflow Providers FabWeb server / proxy
Affected:< 3.7.3

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check installed FAB provider version
    Run: pip show apache-airflow-providers-fab | grep Version, or check your requirements/pip lock file
    Affected if Version is lower than 3.7.3 (e.g., 3.7.2, 3.7.1, etc.)
  2. Confirm FAB auth manager is in use
    Inspect your Airflow configuration (airflow.cfg) or environment variables for webserver auth_backend or check if FAB security manager is enabled
    Affected if Using FAB as the auth manager for Airflow webserver authentication
  3. Verify Azure AD OAuth is configured
    Look for Azure AD related configuration: check for 'oauth' provider in your config, look for Azure AD tenant/client ID settings, or inspect the security manager configuration for Azure AD or Microsoft Online OAuth settings
    Affected if Azure AD OAuth is configured as the authentication provider for FAB
  4. Inspect verify_signature setting
    Check your security manager configuration file or Airflow config for the verify_signature parameter under Azure AD/OAuth settings. Look for verify_signature=False or verify_signature not set (using default)
    Affected if verify_signature is explicitly set to False, OR is not explicitly set (relying on default) in versions before 3.7.3

You are affected if you are using Apache Airflow Providers Fab version less than 3.7.3 with FAB auth manager and Azure AD OAuth, where verify_signature is either set to False or uses the pre-3.7.3 default (False), allowing acceptance of unsigned or forged tokens.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 3.7.3 or later
Fixed in 3.7.3
Interim mitigation

Upgrade apache-airflow-providers-fab to version 3.7.3 or later immediately, as this version sets verify_signature=True by default. Prior to upgrade, confirm no other authentication bypasses exist and review Azure AD OAuth configuration.

Recommended fix High confidence

apache-airflow-providers-fab 3.7.3

  1. Upgrade the `apache-airflow-providers-fab` package to version 3.7.3 or later using your package manager (e.g., `pip install apache-airflow-providers-fab>=3.7.3`)
  2. After upgrading, verify that the Azure AD OAuth login path is working correctly with signature verification enabled by default
  3. If you previously set `verify_signature=False` explicitly in your configuration, review and update your configuration to use the new secure default or remove the explicit override
  4. Restart the Airflow webserver and scheduler services to apply the updated package
Caveat Enabling signature verification by default may cause authentication failures if the Azure AD tenant is misconfigured; ensure the OpenID Connect configuration is valid

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Apache Airflow Providers Fab Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing3.0 h
  • Review / QA2.0 h
8.0 hours of engineering $1,390
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-59243 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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