{"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":0.00571,"epssPercentile":0.45983,"ingestedAt":"2026-07-10T13:49:11.189Z","slug":"CVE-2026-42359","body":"## Overview\n\nA 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.\n\n## Affected packages\n\n- `apache-airflow >= 3.2.0, < 3.2.2`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `apache-airflow 3.2.2`","depth":"twilight","depthScore":49,"depthScoreParts":{"impact":48.4,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}