# Elasticsearch 8.19.20, 9.4.5 Security Update (ESA-2026-119)

**URL:** <https://discuss.elastic.co/t/elasticsearch-8-19-20-9-4-5-security-update-esa-2026-119/389498>\
**Category:** Security Announcements\
**Created:** [August 13, 2026, 10:46am UTC](https://discuss.elastic.co/t/elasticsearch-8-19-20-9-4-5-security-update-esa-2026-119/389498 "2026-08-13T10:46:56Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![ikakavas](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/ikakavas/32/34430_2.png) [@ikakavas](https://discuss.elastic.co/u/ikakavas)\
**Post date:** [August 13, 2026, 10:46am UTC](https://discuss.elastic.co/t/elasticsearch-8-19-20-9-4-5-security-update-esa-2026-119/389498/1 "2026-08-13T10:46:56Z")

</div>

**Uncontrolled Recursion in Elasticsearch Leading to Denial of Service**

Uncontrolled Recursion (CWE-674) in Elasticsearch can lead to denial of service via Input Data Manipulation (CAPEC-153). An authenticated user holding only low-privileged index creation permissions can submit a single request containing a specially crafted, malformed custom analysis definition that is resolved recursively without a cycle or depth check, exhausting the thread stack and terminating the affected node.

**Affected Versions:**

> - 8.x: All versions from 8.0.0 up to and including 8.19.19
> - 9.x: All versions from 9.0.0 up to and including 9.4.4

**Affected Configurations:**

All configurations are affected. The custom analysis capability is part of index settings and is available by default; exploitation requires only the privilege to create an index.

**Solutions and Mitigations:**

The issue is resolved in versions 8.19.20 and 9.4.5.

**For Users that Cannot Upgrade:**

There are no workarounds

**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 ( 6.5 ) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H  
**CVE ID:** CVE-2026-72638  
**Problem Type:** CWE-674 - Uncontrolled Recursion  
**Impact:** CAPEC-153 - Input Data Manipulation