CVE-2020-13927: Apache airflow Authentication Bypass Vulnerability

CRITICAL
Advisory Identifier: GHSA-hhx9-p69v-cx2j
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CVSS 9.8
CWE-287 CWE-1056 CWE-1188 CWE-306
Published
Advisory Summary

CVE-2020-13927 is a CRITICAL (CVSS 9.8) authentication bypass vulnerability (CWE-287: Improper Authentication) affecting Apache airflow libraries in the PyPI ecosystem. The issue involves authentication bypass in apache airflow. Remediation is available by upgrading affected packages to version 1.10.11.

CVE-2020-13927 at a Glance

CVE Identifier CVE-2020-13927
GHSA Identifier GHSA-hhx9-p69v-cx2j
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-287: Improper Authentication
Affected Product Apache airflow
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 9.8

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2020-13927

To remediate this vulnerability, upgrade all affected Apache airflow dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

apache-airflow fixed: 1.10.11 
pip install apache-airflow>=1.10.11
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show apache-airflow

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2020-13927, inspect your installed packages using pip:

pip show apache-airflow

Analyze the terminal output to locate any version of Apache airflow in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.10.11), your application is affected.

Note: The pip show apache-airflow command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-287: Improper Authentication, where when an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. In Apache airflow, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

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

CVE-2020-13927 Affected Apache airflow Versions

1 component(s)
Fixed Versions:
1.10.11
Product / Package Ecosystem Affected Versions Fixed Version
apache-airflow
pypi/apache-airflow
PyPI
< 1.10.11
1.10.11

References

NVD — CVE-2020-13927 NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-13927
Apache airflow Source Repository REPOSITORY
https://github.com/apache/airflow/pull/9611
Security Fix Commit FIX COMMIT
https://github.com/apache/airflow/commit/180bca4f993b7b778a8d2c65d3d357652218922b
Security Fix Commit FIX COMMIT
https://github.com/apache/airflow/commit/9e305d6b810a2a21e2591a80a80ec41acb3afed0
Apache airflow Security Information SECURITY
https://airflow.apache.org/docs/apache-airflow/1.10.11/security.html#api-authentication
GitHub Advisory / Wiki ADVISORY
https://github.com/advisories/GHSA-hhx9-p69v-cx2j
Apache airflow Source Repository REPOSITORY
https://github.com/apache/airflow
Apache airflow Release RELEASE
https://github.com/apache/airflow/releases/tag/1.10.11
Apache airflow Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/apache-airflow/PYSEC-2020-18.yaml
lists.apache.org/thread.html/r23a81b... WEB
https://lists.apache.org/thread.html/r23a81b247aa346ff193670be565b2b8ea4b17ddbc7a35fc099c1aadd%40%3Cdev.airflow.apache.org%3E
www.cisa.gov/known-exploited-vul... WEB
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-13927
Apache airflow Security Information SECURITY
http://packetstormsecurity.com/files/162908/Apache-Airflow-1.10.10-Remote-Code-Execution.html
Apache airflow Security Information SECURITY
http://packetstormsecurity.com/files/174764/Apache-Airflow-1.10.10-Remote-Code-Execution.html

Frequently Asked Questions

What is CVE-2020-13927?
CVE-2020-13927 is a security vulnerability in Apache airflow involving Authentication bypass in Apache Airflow under CWE-287: Improper Authentication.
Which Apache airflow versions are affected?
Affected versions include releases prior to 1.10.11 across affected packages: apache-airflow.
What version fixes CVE-2020-13927?
Upgrading to 1.10.11 (or the latest patched release for your respective branch) resolves the vulnerability.
Is apache-airflow affected?
Yes, apache-airflow is affected in releases prior to 1.10.11. Upgrade your dependency to 1.10.11 or later.
What is the CVSS score of CVE-2020-13927?
CVE-2020-13927 has a CVSS v3.1 base score of 9.8 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:H.
What CWE is associated with CVE-2020-13927?
CVE-2020-13927 is classified under CWE-287: Improper Authentication (When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.).
How can I check PyPI dependencies for CVE-2020-13927?
Run the dependency tree command: 'pip show apache-airflow'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-hhx9-p69v-cx2j",
  "modified" : "2025-10-22T17:56:14Z",
  "published" : "2021-04-30T17:34:13Z",
  "aliases" : [ "CVE-2020-13927" ],
  "summary" : "Authentication bypass in Apache Airflow",
  "details" : "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",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:H"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:A"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "apache-airflow"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.10.11"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-13927"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/apache/airflow/pull/9611"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/apache/airflow/commit/180bca4f993b7b778a8d2c65d3d357652218922b"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/apache/airflow/commit/9e305d6b810a2a21e2591a80a80ec41acb3afed0"
  }, {
    "type" : "WEB",
    "url" : "https://airflow.apache.org/docs/apache-airflow/1.10.11/security.html#api-authentication"
  }, {
    "type" : "ADVISORY",
    "url" : "https://github.com/advisories/GHSA-hhx9-p69v-cx2j"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/apache/airflow"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/apache/airflow/releases/tag/1.10.11"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/apache-airflow/PYSEC-2020-18.yaml"
  }, {
    "type" : "WEB",
    "url" : "https://lists.apache.org/thread.html/r23a81b247aa346ff193670be565b2b8ea4b17ddbc7a35fc099c1aadd%40%3Cdev.airflow.apache.org%3E"
  }, {
    "type" : "WEB",
    "url" : "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-13927"
  }, {
    "type" : "WEB",
    "url" : "http://packetstormsecurity.com/files/162908/Apache-Airflow-1.10.10-Remote-Code-Execution.html"
  }, {
    "type" : "WEB",
    "url" : "http://packetstormsecurity.com/files/174764/Apache-Airflow-1.10.10-Remote-Code-Execution.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-1056", "CWE-1188", "CWE-287", "CWE-306" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-04-20T19:30:46Z",
    "nvd_published_at" : "2020-11-10T16:15:00Z"
  }
}