{"id":"CVE-2026-42359","state":"PUBLISHED","title":"Apache Airflow: Authenticated RCE via XCom PATCH endpoint — XComUpdateBody missing FORBIDDEN_XCOM_KEYS validator","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.","publishedAt":"2026-06-01T07:49:17.429Z","updatedAt":"2026-06-02T13:03:40.834Z","severity":{"score":8.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"CISA-ADP"},"assigner":"apache","products":["Apache Software Foundation Apache Airflow"],"affected":[{"vendor":"Apache Software Foundation","product":"Apache Airflow","packageName":"apache-airflow","defaultStatus":"unaffected","versions":[{"version":"3.2.0","status":"affected","lessThan":"3.2.2","versionType":"semver"}],"collectionURL":"https://pypi.python.org"}],"references":["https://github.com/apache/airflow/pull/65915","https://lists.apache.org/thread/g8dqykpf1p90tysq8tln4qtkqwb1038s","https://www.cve.org/CVERecord?id=CVE-2026-33858"],"weaknesses":["CWE-502"],"ingestedAt":"2026-10-29T20:11:57.932Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/42xxx/CVE-2026-42359.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-42359","state":"PUBLISHED","datePublished":"2026-06-01T07:49:17.429Z","dateUpdated":"2026-06-02T13:03:40.834Z","assignerShortName":"apache","assignerOrgId":"f0158376-9dc2-43b6-827c-5f631a4d8d09","dateReserved":"2026-04-26T19:37:56.165Z"},"containers":{"cna":{"title":"Apache Airflow: Authenticated RCE via XCom PATCH endpoint — XComUpdateBody missing FORBIDDEN_XCOM_KEYS validator","descriptions":[{"lang":"en","value":"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":[{"vendor":"Apache Software Foundation","product":"Apache Airflow","packageName":"apache-airflow","defaultStatus":"unaffected","versions":[{"version":"3.2.0","status":"affected","lessThan":"3.2.2","versionType":"semver"}],"collectionURL":"https://pypi.python.org"}],"references":[{"url":"https://github.com/apache/airflow/pull/65915","tags":["patch"]},{"url":"https://lists.apache.org/thread/g8dqykpf1p90tysq8tln4qtkqwb1038s","tags":["vendor-advisory"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-33858","tags":["related"]}],"metrics":[{"other":{"content":{"text":"medium"},"type":"Textual description of severity"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-502","description":"CWE-502: Deserialization of Untrusted Data","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"apache","orgId":"f0158376-9dc2-43b6-827c-5f631a4d8d09","dateUpdated":"2026-06-01T15:16:19.161Z"},"credits":[{"lang":"en","type":"finder","value":"Jeff Vier (@boinger)"},{"lang":"en","type":"finder","value":"Anisto Mejin (Izat)"},{"lang":"en","type":"finder","value":"Venkatraman Kumar (r3dw0lfsec), Securin"},{"lang":"en","type":"remediation developer","value":"Jarek Potiuk"}],"source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"airflow-s/generate_cve_json.py"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":8.8,"attackVector":"NETWORK","baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","integrityImpact":"HIGH","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"HIGH","privilegesRequired":"LOW","confidentialityImpact":"HIGH"}},{"other":{"type":"ssvc","content":{"timestamp":"2026-06-02T03:55:43.691388Z","id":"CVE-2026-42359","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-06-02T13:03:40.834Z"}}]}}}