CVE-2026-86829

Apache Airflow: Deserialization of task-controlled XCom values in the Scheduler during dependency evaluation

Published Nov 9, 2026 CVSS 3.1 · 8.8 High EPSS < 1% KEV · Not listed
Description
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

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History
Type Values Removed Values Added
Metrics cvssV3_1

{'score': 8.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'}

Type Values Removed Values Added
First Time appeared Apache
Apache airflow
Vendors & Products Apache
Apache airflow
Type Values Removed Values Added
Description 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.
Title Apache Airflow: Deserialization of task-controlled XCom values in the Scheduler during dependency evaluation
Weaknesses CWE-502
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
apache
Published
Updated
Nov 12, 2026, 7:53 PM
Reserved
Sep 8, 2026, 2:27 PM
Status
Awaiting Analysis
Published
Nov 9, 2026, 10:17 AM
Modified
Nov 12, 2026, 8:18 PM