What is CVE-2026-78606?

CVE-2026-78606 is a medium-severity vulnerability in Elastic Kibana, classified under Incorrect Authorization. CVSS score: 4.2/10. Published 2026-09-01.

How severe is CVE-2026-78606?

Medium severity. CVSS v3 base score is 4.2 out of 10.

Auth bypass in Elastic Kibana

CVE-2026-78606

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.

Vulnerability class: Broken Access Control

Published 2026-09-01 · last modified 2026-09-02.

CVSS v3 metric

CVSS v3 base score 4.2 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.002 (13.2th percentile), scored 2026-10-17.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 13th percentile — 13.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.001

Affected products

Elastic Kibana

Weakness classification (CWE)

CWE-863 — Incorrect Authorization

References

discuss.elastic.co/t/kibana-8-19-21-9-4-6-9-5-2-security-update-esa-2026-142/39… (Vendor Advisory)

Frequently asked questions

What is CVE-2026-78606?: CVE-2026-78606 is a medium-severity vulnerability in Elastic Kibana, classified under Incorrect Authorization. CVSS score: 4.2/10. Published 2026-09-01.
How severe is CVE-2026-78606?: Medium severity. CVSS v3 base score is 4.2 out of 10.