# Kibana 8.19.16, 9.3.5, 9.4.2 Security Update (ESA-2026-35)

**URL:** https://discuss.elastic.co/t/kibana-8-19-16-9-3-5-9-4-2-security-update-esa-2026-35/386554
**Category:** Security Announcements
**Created:** [May 28, 2026, 7:25pm UTC](https://discuss.elastic.co/t/kibana-8-19-16-9-3-5-9-4-2-security-update-esa-2026-35/386554 "2026-05-28T19:25:21Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![ismisepaul](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/ismisepaul/32/102235_2.png) [@ismisepaul](https://discuss.elastic.co/u/ismisepaul)
#### Post date: [May 28, 2026, 7:25pm UTC](https://discuss.elastic.co/t/kibana-8-19-16-9-3-5-9-4-2-security-update-esa-2026-35/386554/1 "2026-05-28T19:25:21Z")

</div>

**Uncontrolled Resource Consumption in Kibana Leading to Denial of Service**

Uncontrolled Resource Consumption (CWE-400) in Kibana can lead to denial of service via Excessive Allocation (CAPEC-130). An authenticated user can send a specially crafted compressed request payload that is processed prior to authorization checks, causing excessive memory and CPU resource consumption that can result in a Kibana instance becoming unresponsive or crashing.

**Affected Versions:**

- 8.x: All versions from 8.0.0 up to and including 8.19.15
- 9.x:
  - All versions from 9.0.0 up to and including 9.3.4
  - All versions from 9.4.0 up to and including 9.4.1

**Affected Configurations:**

- All configurations of Kibana accessible to authenticated users are affected.

**Solutions and Mitigations:**

The issue is resolved in versions 8.19.16, 9.3.5, and 9.4.2.

**For Users that Cannot Upgrade:**

- There are no workarounds for this vulnerability.

**Indicators of Compromise (IOC)**

Users can monitor for unusual spikes in Kibana memory and CPU utilization, unexpected Kibana process crashes or restarts, and an abnormal volume of large compressed requests in Kibana's access logs.

**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-2026-42400  
**Problem Type:** CWE-400 - Uncontrolled Resource Consumption  
**Impact:** CAPEC-130 - Excessive Allocation