CVE-2026-78603: Auth Bypass (CVSS 4.3)

Description

Missing Authorization (CWE-862) in Kibana can lead to information disclosure via Exploiting Incorrectly Configured Access Control Security Levels (CAPEC-180). An authenticated user holding minimal Elasticsearch privileges could bypass Kibana feature authorization and space access controls, resulting in the unauthorized disclosure of Fleet deployment metadata from the default Kibana space.

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CVSS v3.1 Score

4.3

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

EPSS — Exploit Prediction

0.0017

Probability of exploitation

0.07%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-862 Missing Authorization

References

Other References

https://discuss.elastic.co/t/kibana-9-4-6-9-5-1-security-update-esa-2026-149/390069

Frequently Asked Questions

What is CVE-2026-78603? +

Missing Authorization (CWE-862) in Kibana can lead to information disclosure via Exploiting Incorrectly Configured Access Control Security Levels (CAPEC-180). An authenticated user holding minimal Elasticsearch privileges could bypass Kibana feature authorization and space access controls, resulting in the unauthorized disclosure of Fleet deployment metadata from the default Kibana space. It has a CVSS v3.1 base score of 4.3 (MEDIUM).

How severe is CVE-2026-78603? +

CVE-2026-78603 has a CVSS v3.1 score of 4.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0017, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-78603? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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