---
id: CVE-2026-42359
aliases:
  - GHSA-wr76-29cr-67w8
  - BIT-airflow-2026-42359
  - PYSEC-2026-185
title: Apache Airflow has a Deserialization of Untrusted Data vulnerability
summary: Apache Airflow has a Deserialization of Untrusted Data vulnerability
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
vendor: apache-airflow
product: apache-airflow
ecosystem: pip
affected:
  - 'apache-airflow >= 3.2.0, < 3.2.2'
patched:
  - apache-airflow 3.2.2
published: '2026-06-01'
updated: '2026-07-09'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-wr76-29cr-67w8'
references:
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-42359'
  - url: 'https://github.com/apache/airflow/pull/65915'
  - url: 'https://github.com/apache/airflow'
  - url: >-
      https://github.com/pypa/advisory-database/tree/main/vulns/apache-airflow/PYSEC-2026-185.yaml
  - url: 'https://lists.apache.org/thread/g8dqykpf1p90tysq8tln4qtkqwb1038s'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-33858'
tags:
  - osv
  - pip
epss: 0.00947
epssPercentile: 0.59471
ingestedAt: '2026-07-10T13:49:11.189Z'
---

## Overview

A bug in Apache Airflow's XCom PATCH endpoint `PATCH /api/v2/xcomEntries/{key}` allowed an authenticated UI/API user with XCom write permission on a Dag to set XCom entries under reserved key names (e.g. `return_value`) that the matching POST endpoint already validated against `FORBIDDEN_XCOM_KEYS`. The endpoint also accepted serialized payload shapes the triggerer's deserializer treats as code; combined, this allowed RCE on the triggerer when the affected task next deferred. Affects deployments where untrusted users have XCom write permission on Dags that defer to the triggerer. This is a fix-bypass of CVE-2026-33858: PR #64148 added the `FORBIDDEN_XCOM_KEYS` validator only on the POST/set path; the PATCH path was not covered. Users who already upgraded for CVE-2026-33858 should additionally upgrade to `apache-airflow` 3.2.2 or later to cover the PATCH-path bypass.

## Affected packages

- `apache-airflow >= 3.2.0, < 3.2.2`

## Remediation

Upgrade to a patched release:

- `apache-airflow 3.2.2`