RCE via Prototype Pollution in OpenSearch Dashboards

{
  "id": "cbd054df0d93f44e82fdee6a797a4c3151a161fdee87c7f623ddd2a6454be5ea",
  "url": "https://osv.dev/vulnerability/CVE-2026-18420",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "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.",
    "evidence": "osv:CVE-2026-18420",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-18420",
      "aliases": [
        "CVE-2026-18420",
        "GHSA-xmqx-xq2p-8jq2"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "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"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/opensearch-project/opensearch-dashboards",
              "type": "GIT",
              "events": [
                {
                  "introduced": "c378e1f95a58498ad41c4c99f39e2072b2629085"
                },
                {
                  "fixed": "aa72a9818a045ad4e290a5eb9be59e025b90634d"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "3.0.0"
                      },
                      {
                        "fixed": "3.8.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "fixed": "aa72a9818a045ad4e290a5eb9be59e025b90634d"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "3.8.0"
                  }
                ]
              }
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-18420.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:23.774872857Z",
      "provider": "osv",
      "references": [
        "https://aws.amazon.com/security/security-bulletins/2026-085-aws/",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/18xxx/CVE-2026-18420.json",
        "https://github.com/opensearch-project/OpenSearch-Dashboards/security/advisories/GHSA-xmqx-xq2p-8jq2",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-18420",
        "https://github.com/opensearch-project/OpenSearch-Dashboards/releases/tag/3.8.0"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-1321"
        ],
        "cna_assigner": "AMZN",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/18xxx/CVE-2026-18420.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-18420",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 490063,
  "published_at": "2026-08-20T20:40:40.709+00:00"
}