# Kibana 8.16.3, 8.17.2 Security Update (ESA-2026-51)

**URL:** <https://discuss.elastic.co/t/kibana-8-16-3-8-17-2-security-update-esa-2026-51/387446>\
**Category:** Security Announcements\
**Created:** [July 1, 2026, 2:03pm UTC](https://discuss.elastic.co/t/kibana-8-16-3-8-17-2-security-update-esa-2026-51/387446 "2026-07-01T14:03:47Z")\
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**Author:** ![kruskall](https://avatars.discourse-cdn.com/v4/letter/k/ac91a4/32.png) [@kruskall](https://discuss.elastic.co/u/kruskall)\
**Post date:** [July 1, 2026, 2:03pm UTC](https://discuss.elastic.co/t/kibana-8-16-3-8-17-2-security-update-esa-2026-51/387446/1 "2026-07-01T14:03:47Z")

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**Authorization Bypass Through User-Controlled Key in Kibana Leading to Unauthorized Data Modification**

Authorization Bypass Through User-Controlled Key (CWE-639) in Kibana can lead to unauthorized data modification via Accessing Functionality Not Properly Constrained by ACLs (CAPEC-1). Under certain conditions, an authenticated user could reference another user's AI Assistant conversation identifier to access or modify a conversation they do not own. Successful exploitation requires knowledge of a hard-to-guess identifier.

**Affected Versions:**

- 8.x:
  - All versions from 8.0.0 up to and including 8.16.2
  - All versions from 8.17.0 up to and including 8.17.1

**Affected Configurations:**

- Affects deployments that use the AI Assistant. Exploitation requires an authenticated account with access to the AI Assistant.

**Solutions and Mitigations:**

The issue is resolved in version 8.16.3 and 8.17.2.

**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-2026-78581  
**Problem Type:** CWE-639 - Authorization Bypass Through User-Controlled Key  
**Impact:** CAPEC-1 - Accessing Functionality Not Properly Constrained by ACLs

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Change log

- 2026-08-25: CVE ID previously said CVE-2026-49089, however the actual CVE number is CVE-2026-78581

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