# CVE-2026-86829: Apache Airflow: Deserialization of task-controlled XCom values in the Scheduler during dependency evaluation

Status: published. Published: 2026-11-09. Updated: 2026-11-09.

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

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: apache) — https://github.com/apache/airflow/pull/72718

## Affected products and versions

- Apache Software Foundation / Apache Airflow (apache-airflow-core): ≥ 0; < 3.4.0 (affected, semver). Source: CNA: apache

## Severity and prioritization

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-502

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/apache/airflow/pull/72718 (CNA: apache; patch)

- https://lists.apache.org/thread.html/2qbt7qnclrlxtg3f1b685533r3mvk9hv (CNA: apache; vendor-advisory)

- http://www.openwall.com/lists/oss-security/2026/11/09/9 (ADP: CVE)

## Provenance

- CNA: apache: https://www.cve.org/CVERecord?id=CVE-2026-86829; retrieved 2026-11-09; source updated 2026-11-09

Revision: c92534e1bce48889e098afd7d753f656a6f7758383eb72b00230f48ed0e944bf

Canonical: https://y2.dev/cve/CVE-2026-86829

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