Apache Airflow: Unsafe Deserialization via Legacy Serialization Keys (type/var) Bypass in XCom API

CVE-2026-33858 · Published Apr 13, 2026 · updated Jun 5, 2026

High8.8

Fix: upgrade to 3.2.0 or later

Dag Authors, who normally should not be able to execute code in the webserver context could craft XCom payload causing the webserver to execute arbitrary code. Since Dag Authors are already highly trusted, severity of this issue is Low.

Users are recommended to upgrade to Apache Airflow 3.2.0, which resolves this issue.

Affected versions

Package	Affected	Fixed in
apache-airflow PyPI	>= 3.1.8, < 3.2.0	3.2.0

Details and references

CVSS 3.1: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Severity from: GitHub (reviewed advisory)
Weakness: CWE-502
Also known as: BIT-airflow-2026-33858, CVE-2026-33858, PYSEC-2026-20

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