Vulnerability record · CVE-2026-18420 · published 20 August 2026

CVE-2026-18420: Prototype pollution vulnerability

Improper input validation in the Time Series Visual Builder (TSVB) plugin in OpenSearch Dashboards allows an authenticated remote user to execute arbitrary code on the server via a crafted JSON payload to the metrics visualization API endpoint. This issue is a form of prototype pollution that enables remote code execution. To remediate this issue, users should upgrade to OpenSearch Dashboards 3.8 or later.

8.7 CVSS 4.0 High EPSS 0.66% · top 50.3% CWE-1321 · Prototype pollution Awaiting Analysis

8.7CVSS 4.0 base score

0.66%EPSS exploitation probability, 30 days

NoNot in CISA KEV

0Affected product versions listed by NVD

3References

25 Aug 2026Last modified by NVD

Description

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

References

Link	Tags
https://aws.amazon.com/security/security-bulletins/2026-085-aws/
https://github.com/opensearch-project/OpenSearch-Dashboards/releases/tag/3.8.0
https://github.com/opensearch-project/OpenSearch-Dashboards/security/advisories/GHSA-xmqx-xq2p-8jq2

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Same products first, then exploited flaws of the same weakness class.

8.6CVE-2026-34621Adobe Acrobat Reader prototype pollution leads to code executionAdobe Acrobat and Reader (versions 24.001.30356, 26.001.21367 and earlier) are affected by prototype pollution (CWE-1321) that can result in arbitrar…KEVEPSS 2.2%analysed11 Apr 2026

Source: NIST National Vulnerability Database (record CVE-2026-18420), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.