# Elasticsearch 8.18.0, 9.0.0 Security Update (ESA-2026-111)

**URL:** <https://discuss.elastic.co/t/elasticsearch-8-18-0-9-0-0-security-update-esa-2026-111/389495>\
**Category:** Security Announcements\
**Created:** [August 13, 2026, 10:46am UTC](https://discuss.elastic.co/t/elasticsearch-8-18-0-9-0-0-security-update-esa-2026-111/389495 "2026-08-13T10:46:46Z")\
**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-8-18-0-9-0-0-security-update-esa-2026-111/389495/1 "2026-08-13T10:46:46Z")

</div>

**Memory Allocation with Excessive Size Value in Elasticsearch Leading to Denial of Service**

Memory Allocation with Excessive Size Value (CWE-789) in the ES|QL query processing of Elasticsearch can lead to denial of service via Excessive Allocation (CAPEC-130). An authenticated user able to submit ES|QL queries could send a specially crafted query whose evaluation allocates an unbounded amount of heap memory, exhausting the available heap on the receiving node and causing the node to become unavailable.

**Affected Versions:**

> - 8.x: All versions from 8.11.0 up to and including 8.17.9

Versions earlier than 8.11.0 are not affected because the ES|QL query language was introduced in 8.11.0.

**Affected Configurations:**

> - All configurations are affected. ES|QL is enabled by default.
> - Exploitation requires an account that is authorized to run ES|QL queries against the cluster.

**Solutions and Mitigations:**

The issue is resolved in versions 8.18.0 and 9.0.0.

**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.

**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-2026-72656  
**Problem Type:** CWE-789 - Memory Allocation with Excessive Size Value  
**Impact:** CAPEC-130 - Excessive Allocation