# Elasticsearch 8.19.19, 9.3.8, 9.4.4 Security Update (ESA-2026-188)

**URL:** <https://discuss.elastic.co/t/elasticsearch-8-19-19-9-3-8-9-4-4-security-update-esa-2026-188/390861>\
**Category:** Security Announcements\
**Created:** [October 6, 2026, 6:37pm UTC](https://discuss.elastic.co/t/elasticsearch-8-19-19-9-3-8-9-4-4-security-update-esa-2026-188/390861 "2026-10-06T18:37:40Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![cronosda](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/cronosda/32/147882_2.png) [@cronosda](https://discuss.elastic.co/u/cronosda)\
**Post date:** [October 6, 2026, 6:37pm UTC](https://discuss.elastic.co/t/elasticsearch-8-19-19-9-3-8-9-4-4-security-update-esa-2026-188/390861/1 "2026-10-06T18:37:40Z")

</div>

**Incorrect Authorization in Elasticsearch Leading to Unauthorized Data Stream Modification**

Incorrect Authorization (CWE-863) in Elasticsearch can lead to unauthorized data stream modification via Accessing Functionality Not Properly Constrained by ACLs (CAPEC-1). An authenticated user with sufficient privileges over a single resource could use the Modify Data Streams API to modify a data stream to which they were not otherwise authorized, potentially injecting data into it or affecting its ability to be searched normally. This issue does not allow an attacker to read the contents of a data stream they do not otherwise have access to.

**Affected Versions:**

> - 7.x:

- All versions from 7.17.5 up to and including 7.17.29

> No fix is available for the 7.17.x line. Users should upgrade to a supported release line.

> - 8.x: All versions from 8.2.2 up to and including 8.19.18
> - 9.x:

- All versions from 9.0.0 up to and including 9.3.7
- All versions from 9.4.0 up to and including 9.4.3

**Affected Configurations:**

> - All configurations that use Elasticsearch Security (role-based access control) together with data streams are affected. No non-default configuration is required to trigger this issue.

**Solutions and Mitigations:**

The issue is resolved in versions 8.19.19, 9.3.8, and 9.4.4.

The versions above are the first releases that contain the fix, and later releases also contain it. Elastic recommends upgrading to the most recent release available, and reviewing the [known issues](https://www.elastic.co/docs/release-notes) for your target version before upgrading.

**For Users that Cannot Upgrade:**

> - There are no workarounds for this vulnerability.

**Indicators of Compromise (IOC)**

No specific indicators of compromise have been identified for this vulnerability.

**Elastic Cloud Serverless**

Due to our continuous deployment and patching model, the vulnerability described in this security advisory was remediated in our Elastic Cloud Serverless offering before the public disclosure.

**Severity:** CVSSv3.1: Medium ( 5.4 ) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L  
**CVE ID:** CVE-2026-102407  
**Problem Type:** CWE-863 - Incorrect Authorization  
**Impact:** CAPEC-1 - Accessing Functionality Not Properly Constrained by ACLs