{"id":"CVE-2026-103009","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-103009","generatedAt":"2026-10-28T01:12:28.267Z","title":"Authorization Bypass Through User-Controlled Key (CWE-639) in Elasticsearch can lead to Information Disclosure via a specially crafted cross-cluster search request that references an unauthorized shard identifier.","description":"Authorization Bypass Through User-Controlled Key (CWE-639) in Elasticsearch can lead to Information Disclosure via a specially crafted cross-cluster search request that references an unauthorized shard identifier. Elasticsearch contains an authorization bypass weakness in its handling of cross-cluster search requests made through the Remote Cluster Security (RCS) 2.0 model. An authorization check validates a request against one identifying attribute of the target shard, while a separate, independently-supplied identifying attribute in the same request determines which shard is actually accessed. A holder of a cross-cluster API key authorized for one index can craft a request whose two identifying attributes refer to different indices, causing the request to be authorized against an index they can access while actually operating against a different, unauthorized index. This can expose that index's document contents, field mappings, and other metadata, and in limited cases allows modification of retention-lease state on the unauthorized index.","published":"2026-10-06T20:17:14.000Z","lastModified":"2026-10-09T13:13:05.000Z","status":"Analyzed","sourceIdentifier":"security@elastic.co","cvss":{"version":"3.1","score":7.1,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N"},"cwe":["CWE-639"],"affected":["elastic/elasticsearch"],"epss":{"score":0.00231,"percentile":0.13814,"date":"2026-10-26","history":[{"date":"2026-10-07","score":0.00243,"percentile":0.14214}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.23%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[{"kind":"new","label":"New CVE","at":"2026-10-06T20:17:14.000Z","detail":{"score":"7.1","severity":"HIGH","publishedAt":"2026-10-06T20:17:14.247Z"},"summary":"New CVE, high severity (CVSS 7.1)."}],"references":[{"url":"https://discuss.elastic.co/t/elasticsearch-8-19-23-9-4-8-9-5-5-security-update-esa-2026-199/390874","tags":["Vendor Advisory"],"source":"security@elastic.co"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-103009","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}