CVE-2021-38540 Apache Airflow: Variable Import endpoint missed authentication check
Unauthenticated attackers can modify Airflow variables via the import endpoint, leading to potential remote code execution, data modification, or denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2021-38540?
CVE-2021-38540 is a critical missing authorization vulnerability in Apache Airflow, published on 9 Sep 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
The variable import endpoint was not protected by authentication in Airflow >=2.0.0, <2.1.3. This allowed unauthenticated users to hit that endpoint to add/modify Airflow variables used in DAGs, potentially resulting in a denial of service, information disclosure or remote code execution. This issue affects Apache Airflow >=2.0.0, <2.1.3.
Which versions are affected by CVE-2021-38540?
4 open source packages ship an affected version, including apache-airflow and airflow. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
apache-airflow PyPI | From 2.0.0 | 2.1.3 |
apache-airflow PyPI | From 2.0.0 | 2.1.3 |
apache-airflow PyPI | From 2.0.0 | 2.1.3 |
airflow Bitnami | From 2.0.0 | 2.1.3 |
Products include Apache Airflow.
How do I fix CVE-2021-38540?
Upgrade apache-airflow to 2.1.3 or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2021-38540 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-38540 exists.
Public exploit code: 1 Nuclei template and 1 proofs of concept on GitHub.
Other vulnerabilities in Apache Airflow
- CVE-2020-13927 Apache Airflow's Experimental API Authentication Bypass
- CVE-2020-11978 Apache Airflow Command Injection
- CVE-2026-33264 Apache Airflow: DAG author RCE on webserver via unrestricted import_string() in BaseSerialization.deserialize()
- CVE-2023-25754 Apache Airflow: Privilege escalation using airflow logs
- CVE-2023-22884 Apache Airflow, Apache Airflow MySQL Provider: Arbitrary file read via MySQL provider in Apache Airflow
Sources
Also known as BIT-airflow-2021-38540, GHSA-h88f-r7cw-8fv3, PYSEC-2021-326.