{"id":"BIT-airflow-2026-42359","summary":"Apache Airflow: Authenticated RCE via XCom PATCH endpoint — XComUpdateBody missing FORBIDDEN_XCOM_KEYS validator","details":"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.","aliases":["CVE-2026-42359","GHSA-wr76-29cr-67w8","PYSEC-2026-185"],"modified":"2026-09-08T08:45:38.728221582Z","published":"2026-06-05T05:40:40.845Z","database_specific":{"severity":"High","cpes":["cpe:2.3:a:apache:airflow:*:*:*:*:*:python:*:*"]},"references":[{"type":"FIX","url":"https://github.com/apache/airflow/pull/65915"},{"type":"ADVISORY","url":"https://lists.apache.org/thread/g8dqykpf1p90tysq8tln4qtkqwb1038s"},{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-42359"},{"type":"ADVISORY","url":"https://www.cve.org/CVERecord?id=CVE-2026-33858"}],"affected":[{"package":{"name":"airflow","ecosystem":"Bitnami","purl":"pkg:bitnami/airflow"},"ranges":[{"type":"SEMVER","events":[{"introduced":"3.2.0"},{"fixed":"3.2.2"}]}],"database_specific":{"source":"https://github.com/bitnami/vulndb/tree/main/data/airflow/BIT-airflow-2026-42359.json"},"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}],"schema_version":"1.9.0"}