Authenticated code execution via TSVB prototype pollution
Published Aug 20, 2026 · Updated Aug 20, 2026
Prototype pollution in OpenSearch Dashboards before 3.8.0 allows remote authenticated users to execute code via the TSVB metrics API. AWS identifies the Time Series Visual Builder metrics visualization endpoint as accepting crafted JSON that can modify object prototype attributes and reach server-side code execution, but the specific field path or merge operation has not been disclosed publicly. Exploitation requires valid OpenSearch Dashboards access with standard data permissions and network reachability to the API; no user interaction is required, and compromise is bounded to the affected Dashboards server or managed service instance.
Summary
What happened
Prototype pollution in OpenSearch Dashboards before 3.8.0 allows remote authenticated users to execute code via the TSVB metrics API. AWS identifies the Time Series Visual Builder metrics visualization endpoint as accepting crafted JSON that can modify object prototype attributes and reach server-side code execution, but the specific field path or merge operation has not been disclosed publicly. Exploitation requires valid OpenSearch Dashboards access with standard data permissions and network reachability to the API; no user interaction is required, and compromise is bounded to the affected Dashboards server or managed service instance.
The record
- CVE
- CVE-2026-18420
- Published
- Aug 20, 2026
- Updated
- Aug 20, 2026
- Vendor
- OpenSearch Software Foundation
- Product
- OpenSearch Dashboards
- Classifications
- CWE-1321, CAPEC-586, T1190
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Aug 20, 2026CVE publishedPublication date reported by the CVE source.
- Aug 20, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=3.0.0 <3.8.0
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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