CVE-2026-84942CWE-79cross-site-scripting

CVE-2026-84942

High · published September 9, 2026

CVSS v3.1
8.7
EPSS
1%
Percentile
44.9
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
8.7 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
CVSS v4.0
6.3 · CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N
EPSS
0.00544 · 44.9th percentile
Weakness
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Published
2026-09-09T00:18Z
References (3)
https://aws.amazon.com/security/security-bulletins/2026-102-aws/ · ff89ba41-3aa1-4d27-914a-91399e9639e5https://github.com/opensearch-project/OpenSearch-Dashboards/releases/tag/2.19.5 · ff89ba41-3aa1-4d27-914a-91399e9639e5https://github.com/opensearch-project/OpenSearch-Dashboards/releases/tag/3.6.0 · ff89ba41-3aa1-4d27-914a-91399e9639e5
EPSS history
Timeline
  • 10 SEP 03:18Z
    EPSS moved — → 0%
    epss
  • 08 SEP 19:41Z
    Stored Cross-Site Scripting via Vega Expression Function Bypass in OpenSearch Dashboards
    cvelistv5