---
id: "CVE-2026-86829"
page: "https://infrastack.ai/live/CVE-2026-86829"
kind: "vulnerability"
aliases: ["CVE-2026-86829"]
title: "Apache Airflow: scheduler deserializes task-written XCom values, letting DAG authors escalate"
severity: "high"
cvss: null
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["apache-airflow", "data-pipelines", "package", "python", "self-hosted"]
not_affected_if: ["fully-trusted-dag-authors", "no-xcom-dependencies"]
published_at: "2026-11-09T10:17:13+00:00"
first_seen_at: "2026-11-09T10:25:50+00:00"
updated_at: "2026-11-09T10:26:30+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-86829", "first_seen_at": "2026-11-09T10:25:50+00:00"}]
exploit_sources: []
---

# Apache Airflow: scheduler deserializes task-written XCom values, letting DAG authors escalate

Link for people: https://infrastack.ai/live/CVE-2026-86829 (this .md is for agents)

Apache Airflow's scheduler fully deserializes XCom values that task code writes while it checks task dependencies. A DAG author, who should only control worker-level execution, can therefore feed crafted data into code running inside the scheduler process.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed version with `airflow version` or `pip show apache-airflow`
- Check whether any task dependency reads a task-written XCom value (for example a dependency or sensor that calls XCom pull), since the scheduler must evaluate such a dependency to be exposed
- Check whether DAG authors are trusted less than Deployment Managers in your deployment

## Fix

- apache-airflow: upgrade to `3.4.0` or later, which restricts dependency evaluation to primitive XCom values

## Timeline

- 2026-11-09T10:25:50+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-86829

## From the sources

Apache Airflow's scheduler fully deserializes XCom values written by task code while evaluating task dependencies. A Dag author, who controls what a task writes to XCom, therefore controls data that is deserialized inside the scheduler process - a context the Airflow security model reserves for code installed by the Deployment Manager, above the worker-scoped execution capability a Dag author is documented to have. Deployments that treat Dag authors as less trusted than Deployment Managers are affected, and the scheduler must be evaluating a task dependency that reads a task-written XCom value. Users of apache-airflow are recommended to upgrade to version 3.4.0 or later, which restricts dependency evaluation to primitive XCom values.

---

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