# Kibana 8.19.21, 9.4.6, 9.5.2 Security Update (ESA-2026-142)

**URL:** <https://discuss.elastic.co/t/kibana-8-19-21-9-4-6-9-5-2-security-update-esa-2026-142/390093>\
**Category:** Security Announcements\
**Created:** [September 1, 2026, 6:47pm UTC](https://discuss.elastic.co/t/kibana-8-19-21-9-4-6-9-5-2-security-update-esa-2026-142/390093 "2026-09-01T18:47:08Z")\
**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:** [September 1, 2026, 6:47pm UTC](https://discuss.elastic.co/t/kibana-8-19-21-9-4-6-9-5-2-security-update-esa-2026-142/390093/1 "2026-09-01T18:47:09Z")

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**Incorrect Authorization in Kibana Leading to Unauthorized Disclosure, Modification, and Deletion of Data**

Incorrect Authorization (CWE-863) in Kibana can lead to unauthorized disclosure, modification, and deletion of data via Accessing Functionality Not Properly Constrained by ACLs (CAPEC-1). Where two authenticated principals originating from different authentication realms share the same username value, one could read, modify, and delete the other's private Elastic AI Assistant Knowledge Base entries.

**Affected Versions:**

> - 8.x: All versions from 8.19.11 up to and including 8.19.20
> - 9.x:

- All versions from 9.3.0 up to and including 9.4.5
- All versions from 9.5.0 up to and including 9.5.1

**Affected Configurations:**  
Deployments that have multiple authentication realms configured, where distinct authenticated principals in separate realms share the same username value, and where those principals hold a role granting access to the Elastic AI Assistant feature. Deployments configured with only a single authentication realm are not affected.

**Solutions and Mitigations:**

The issue is resolved in Kibana versions 8.19.21, 9.4.6, and 9.5.2.

**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 ( 4.2 ) - CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N  
**CVE ID:** CVE-2026-78606  
**Problem Type:** CWE-863 - Incorrect Authorization  
**Impact:** CAPEC-1 - Accessing Functionality Not Properly Constrained by ACLs