What is CVE-2021-35936?

CVE-2021-35936 is a medium-severity vulnerability in Apache Airflow, classified under Information Disclosure. CVSS score: 5.3/10. Published 2021-08-16.

How severe is CVE-2021-35936?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Auth bypass in Apache Airflow

CVE-2021-35936

If remote logging is not used, the worker (in the case of CeleryExecutor) or the scheduler (in the case of LocalExecutor) runs a Flask logging server and is listening on a specific port and also binds on 0.0.0.0 by default. This logging server had no authentication and allows reading log files of DAG jobs. This issue affects Apache Airflow < 2.1.2.

Vulnerability class: Information Disclosure

Published 2021-08-16 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.054 (92.5th percentile), scored 2026-10-07.

Low probability of exploitation in the next 30 days, but still tracked. 93rd percentile — 92.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.040 · newest: 0.054 · change: +0.014

Affected products

Apache Airflow
Apache Software Foundation Airflow — versions Apache Airflow

Weakness classification (CWE)

References

lists.apache.org/thread.html/r53d6bd7b0a66f92ddaf1313282f10fec802e71246606dd30c… (Mailing List, Vendor Advisory)

Frequently asked questions

What is CVE-2021-35936?: CVE-2021-35936 is a medium-severity vulnerability in Apache Airflow, classified under Information Disclosure. CVSS score: 5.3/10. Published 2021-08-16.
How severe is CVE-2021-35936?: Medium severity. CVSS v3 base score is 5.3 out of 10.