CVE-2021-38540Apache Airflow: Variable Import endpoint missed authentication check
- 9.8CriticalCVSS base score
- 80.9%Exploitation in 30 daysEPSS · top 0.4% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- 1Public exploitsMetasploit, Nuclei and Exploit-DB
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.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. The public collections list a Nuclei template for it.
Show the exploits1
Nuclei templates1 template
- Apache Airflow - Unauthenticated Variable Import (Nuclei template) (opens in a new tab)
http/cves/2021/CVE-2021-38540.yamlSeverity critical
Modules, templates and exploits as listed by the Metasploit Framework (BSD-3-Clause), ProjectDiscovery's Nuclei templates (MIT) and the Exploit Database (GPLv2), read once a day. Where the data comes from
Timeline
ID reserved
By apache
- 29 days later
· 29 days later
Published
- 3 years later
· 3 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.1 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 80.9% · top 0.4% of all CVEs (12 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.8.
Affected products
Apache Software Foundation · Apache Airflow
- affected Apache Airflow – < 2.1.3
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- PyPIapache-airflowGHSA-h88f-r7cw-8fv3 (opens in a new tab)
What to do
Workaround: Upgrade to Apache Airflow >=2.1.3
References
References2
- https://lists.apache.org/thread.html/rb34c3dd1a815456355217eef34060789f771b6f77c3a3dec77de2064%40%3Cusers.airflow.apache.org%3E (opens in a new tab)x_refsource_MISCx_transferred
- [announce] 20210909 CVE-2021-38540: Apache Airflow: Variable Import endpoint missed authentication check (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2021-0016 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-h88f-r7cw-8fv3 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2021-38540)Record last updated .