---
id: CVE-2026-103009
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
summary: >-
  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 …
severity: high
cvss: 7.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N'
cwe:
  - CWE-639
vendor: Elastic
product: Elasticsearch
affected:
  - Elasticsearch >= 8.13.0 <= 8.19.22
  - Elasticsearch >= 9.0.0 <= 9.4.7
  - Elasticsearch >= 9.5.0 <= 9.5.4
published: '2026-10-06'
updated: '2026-10-06'
sourceUpdated: '2026-10-06T20:17:14.247'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-103009'
references:
  - url: >-
      https://discuss.elastic.co/t/elasticsearch-8-19-23-9-4-8-9-5-5-security-update-esa-2026-199/390874
    label: security@elastic.co
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-06T19:52:05.345727Z'
ingestedAt: '2026-10-06T20:16:42.474Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.