GitHub Advisoryadvisory · PyPI

GHSA-wr76-29cr-67w8 Apache Airflow has a Deserialization of Untrusted Data vulnerability

HIGH Published 2026-06-01 Modified 2026-07-09 Official page ↗
Aliases
CVE-2026-42359
Ecosystem
PyPI
Packages
apache-airflow
Severity
High
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weaknesses
CWE-502
Reviewed
2026-07-09

Affected packages

• PyPI apache-airflow: >= 3.2.0, < 3.2.2 → fixed in 3.2.2

Description

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.

Related

Alias · CVE (1)

  • CVE-2026-42359 A bug in Apache Airflow's XCom PATCH endpoint `PATCH /api/v2/xcomEntries/{key}` allowed an authenticated UI/API user with XCom write… vulnerability

Weakness · CWE (1)

  • CWE-502 Deserialization of Untrusted Data weakness

References