What is CVE-2026-84942?

CVE-2026-84942 is a high-severity vulnerability in Opensearch Dashboards, classified under Cross-site Scripting. CVSS score: 8.7/10. Published 2026-09-08.

How severe is CVE-2026-84942?

High severity. CVSS v3 base score is 8.7 out of 10.

XSS in Opensearch Dashboards

CVE-2026-84942

Improper input validation in the Vega expression function implementation in OpenSearch Dashboards allows a remote authenticated actor with dashboard write permissions to execute arbitrary JavaScript in the context of other users' browser sessions by saving a crafted Vega visualization. The checkForFunctionProperty validation routine failed to recurse into arrays of objects, allowing a function property nested inside an array to bypass validation.

Vulnerability class: XSS (Cross-Site Scripting)

CVSS v3 metric

CVSS v3 base score 8.7 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N.

Affected products

Opensearch Dashboards

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

ff89ba41-3aa1-4d27-914a-91399e9639e5 (patch)
ff89ba41-3aa1-4d27-914a-91399e9639e5 (patch)
ff89ba41-3aa1-4d27-914a-91399e9639e5 (vendor-advisory)

Frequently asked questions

What is CVE-2026-84942?: CVE-2026-84942 is a high-severity vulnerability in Opensearch Dashboards, classified under Cross-site Scripting. CVSS score: 8.7/10. Published 2026-09-08.
How severe is CVE-2026-84942?: High severity. CVSS v3 base score is 8.7 out of 10.