Apache Airflow Experimental API Authentication Bypass and Remote Code Execution (RCE) Vulnerability (CVE-2020-13927)
Executive & SecOps Summary
SECOPS ASSESSMENTApache Airflow versions prior to 1.10.11, and existing installations retaining default configurations
Unauthenticated attackers can access the Experimental API to trigger arbitrary DAGs, leading to full remote code execution (RCE) and server compromise
Upgrade Apache Airflow to version 1.10.11 or higher, or explicitly configure the API authentication backend to 'deny_all' in airflow.cfg
Affected Products & Version Scope
Remediation & Live Workaround Commands
PATCH & WORKAROUND1. Official Patch & Version Upgrade Commands
Upgrade Apache Airflow to version 1.10.11 or later to ensure secure defaults are applied.
# Upgrade Apache Airflow using pip to a secure version\pip install --upgrade 'apache-airflow>=1.10.11'2. Temporary Workaround & Hardening Configuration
If an immediate upgrade is not feasible, manually restrict access by modifying the 'airflow.cfg' configuration file.
# Modify the [api] section in airflow.cfg
[api]
auth_backend = airflow.api.auth.backend.deny_all3. Log Audit & IoC Verification Commands
Audit your web server access logs for unauthorized API requests and verify the current active configuration.
# 1. Search access logs for suspicious Experimental API requests
grep -E '/api/experimental/' /var/log/airflow/webserver_access.log
# 2. Verify the currently active API authentication backend
airflow config get-value api auth_backendBlock Exploits Instantly with Managed Virtual Patching Rules
Can't patch production immediately? Deploy managed WAF rules at the edge to intercept RCE, SQLi, and deserialization payloads before they hit your origin server.
Technical Root Cause & Exploitation Mechanics
1. Vulnerability Overview & Root Cause
In Apache Airflow versions prior to 1.10.11, the default configuration for the Experimental API was set to allow all API requests without requiring any authentication. This insecure default configuration (CWE-306, CWE-1188) exposes critical orchestration endpoints to unauthorized users.
2. Exploitation Mechanics & Attack Scenario
An attacker can send unauthenticated HTTP POST requests directly to the '/api/experimental/dags/<DAG_ID>/dag_runs' endpoint. Since no credentials are validated, the attacker can trigger arbitrary DAG runs with custom parameters, allowing them to execute arbitrary OS commands on the underlying worker or webserver nodes.
3. Infrastructure & Business Impact
This vulnerability is highly critical and has been actively exploited in the wild (CISA KEV). Successful exploitation allows complete takeover of the Airflow orchestration server, potentially exposing sensitive database credentials, cloud API keys, and proprietary data pipelines managed by the platform.
Official Vendor Advisories & References
The previous default setting for Airflow's Experimental API was to allow all API requests without authentication, but this poses security risks to users who miss this fact. From Airflow 1.10.11 the default has been changed to deny all requests by default and is documented at https://airflow.apache.org/docs/1.10.11/security.html#api-authentication. Note this change fixes it for new installs but existing users need to change their config to default `[api]auth_backend = airflow.api.auth.backend.deny_all` as mentioned in the Updating Guide: https://github.com/apache/airflow/blob/1.10.11/UPDATING.md#experimental-api-will-deny-all-request-by-default
Frequently Asked SecOps Questions (CVE-2020-13927)
FAQQ1. How critical is CVE-2020-13927 and is it actively exploited in the wild?
CVE-2020-13927 is rated CVSS 9.8 (CRITICAL) with a 30-day EPSS exploitation probability of 99.8%. It is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, requiring immediate emergency remediation.
Q2. Which vendors and products are affected by CVE-2020-13927?
Primary impacted vendors include apache across airflow. Scope summary: Apache Airflow versions prior to 1.10.11. Existing installations require manual configuration changes even after upgrading.
Q3. What temporary mitigations or workarounds exist for CVE-2020-13927 before patching?
[Mitigation] Upgrade Apache Airflow to version 1.10.11 or higher, or explicitly configure the API authentication backend to 'deny_all' in airflow.cfg Follow the CLI remediation commands and interactive SecOps checklist on this page to restrict exposure prior to your maintenance window.
Generate an Internal Engineering Notice or CISO Report for CVE-2020-13927
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