CVE-2026-18420 (GCVE-0-2026-18420)
Vulnerability from cvelistv5 – Published: 2026-08-20 20:40 – Updated: 2026-08-25 19:19
VLAI
EPSS
VEX
Title
RCE via Prototype Pollution in OpenSearch Dashboards
Summary
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.
Severity
SSVC
Exploitation: none
Automatable: no
Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-25 19:18 UTC
CWE
- CWE-1321 - Improperly controlled modification of object prototype attributes ('prototype pollution')
Assigner
References
3 references
| URL | Tags |
|---|---|
| https://github.com/opensearch-project/OpenSearch-… | patch |
| https://github.com/opensearch-project/OpenSearch-… | third-party-advisory |
| https://aws.amazon.com/security/security-bulletin… | vendor-advisory |
Impacted products
2 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| AWS | Amazon OpenSearch Service |
Affected:
3.0.0 , < 3.8.0
(custom)
cpe:2.3:a:aws:amazon_opensearch_service:*:*:*:*:*:*:*:* |
||
| OpenSearch | OpenSearch Dashboards |
Affected:
3.0.0 , < 3.8.0
(custom)
cpe:2.3:a:opensearch:opensearch_dashboards:*:*:*:*:*:*:*:* |
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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