CVE-2026-18420
RCE via Prototype Pollution in OpenSearch Dashboards
Description
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.
INFO
Published Date :
Aug. 20, 2026, 9:17 p.m.
Last Modified :
Aug. 20, 2026, 9:17 p.m.
Remotely Exploit :
Yes !
Source :
ff89ba41-3aa1-4d27-914a-91399e9639e5
Affected Products
The following products are affected by CVE-2026-18420
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | ff89ba41-3aa1-4d27-914a-91399e9639e5 | ||||
| CVSS 3.1 | HIGH | MITRE-CVE | ||||
| CVSS 4.0 | HIGH | ff89ba41-3aa1-4d27-914a-91399e9639e5 | ||||
| CVSS 4.0 | HIGH | ff89ba41-3aa1-4d27-914a-91399e9639e5 |
Solution
- Upgrade OpenSearch Dashboards to version 3.8 or later.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-18420.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-18420 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-18420
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-18420 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-18420 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by ff89ba41-3aa1-4d27-914a-91399e9639e5
Aug. 20, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'AWS', 'product': 'Amazon OpenSearch Service', 'versions': [{'status': 'affected', 'version': '3.0.0', 'lessThan': '3.8.0', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}, {'vendor': 'OpenSearch', 'product': 'OpenSearch Dashboards', 'versions': [{'status': 'affected', 'version': '3.0.0', 'lessThan': '3.8.0', 'versionType': 'custom'}], 'defaultStatus': 'unaffected'}] Added Description 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. Added CVSS V4.0 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:X/V:X/RE:X/U:X Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Added CWE CWE-1321 Added Reference https://aws.amazon.com/security/security-bulletins/2026-085-aws/ Added Reference https://github.com/opensearch-project/OpenSearch-Dashboards/releases/tag/3.8.0 Added Reference https://github.com/opensearch-project/OpenSearch-Dashboards/security/advisories/GHSA-xmqx-xq2p-8jq2