AirflowApplication · Apache
CVE-2021-26559
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 · uneditedImproper Access Control on Configurations Endpoint for the Stable API of Apache Airflow allows users with Viewer or User role to get Airflow Configurations including sensitive information even when `[webserver] expose_config` is set to `False` in `airflow.cfg`. This allowed a privilege escalation attack. This issue affects Apache Airflow 2.0.0.
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 confidenceApache Airflow 2.0.0's Stable API has an improper access control vulnerability on its configuration endpoint. Despite the `[webserver] expose_config` setting being set to `False` in airflow.cfg to hide sensitive configuration, users with Viewer or User roles could still retrieve configuration data including sensitive information through the Stable API, enabling privilege escalation.
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
AirflowApplication
= 2.0.0CVSS 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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
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 checksWork through these to decide whether this CVE applies to you.
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Confirm Airflow versionRun `airflow version` or check the installed Airflow package version to confirm it is exactly 2.0.0Affected if The installed version is Apache Airflow 2.0.0 exactly
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Check if Stable API is enabledInspect the `[api] enable_experimental_api` or similar API configuration setting in airflow.cfg, or check if the `/api/v1/` endpoint is accessibleAffected if The Stable API endpoint is exposed and accessible to users
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Verify expose_config settingCheck the `[webserver] expose_config` option in airflow.cfg - it should be set to `False`Affected if expose_config is set to False but the Stable API still returns configuration data
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Test configuration endpoint accessAs a user with Viewer or User role, make a GET request to the `/api/v1/config` endpoint of the Stable APIAffected if The request returns configuration data including sensitive values despite expose_config being False
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Audit user roles with API accessReview which roles (Viewer, User, Op, Admin) have access to the Stable API endpoints in Airflow's RBAC configurationAffected if Viewer or User roles have permission to access the configuration endpoint
A user is affected if running Airflow 2.0.0, the Stable API is accessible, and users with Viewer or User roles can retrieve configuration data through the API even when expose_config is set to False.
Generated from the published advisory. Verify against your own configuration.
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.
From vendor dataUpgrade Apache Airflow to the patched version. Review access controls and audit logs for any unauthorized configuration access that may have occurred.
Fix this in Airflow
Scoped from the published advisory
- Consultation2.0 h
- Implementation1.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,464.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-26559 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-26559 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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