CVE-2026-42401

Description

Improper Neutralization of Input During Web Page Generation (CWE-79) in Kibana can lead to stored HTML injection. A user with write access to an Elasticsearch index could persist crafted markup which, when subsequently rendered through an affected Kibana view by another user, was not sufficiently sanitized. Successful exploitation could result in unauthorized UI manipulation and outbound network requests issued from the viewing user's browser session.

CVSS v3.1 Score

4.1

MEDIUM

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

EPSS — Exploit Prediction

0.0014

Probability of exploitation

0.04%

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-79 Cross-site Scripting (XSS)

Affected Products

Vendor	Product	Versions
elastic	kibana	8.0.0 — 8.19.16
elastic	kibana	9.0.0 — 9.3.5

References

Advisories & Patches

https://discuss.elastic.co/t/kibana-8-19-16-9-3-5-security-update-esa-2026-34/386552

Frequently Asked Questions

What is CVE-2026-42401? +

Improper Neutralization of Input During Web Page Generation (CWE-79) in Kibana can lead to stored HTML injection. A user with write access to an Elasticsearch index could persist crafted markup which, when subsequently rendered through an affected Kibana view by another user, was not sufficiently sanitized. Successful exploitation could result in unauthorized UI manipulation and outbound network requests issued from the viewing user's browser session. It has a CVSS v3.1 base score of 4.1 (MEDIUM).

How severe is CVE-2026-42401? +

CVE-2026-42401 has a CVSS v3.1 score of 4.1 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0014, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-42401? +

CVE-2026-42401 affects products from elastic, specifically: kibana. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-42401? +

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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