Security advisory

{
  "id": "d856aabe8d0d9510bc945a82dbc4890dd771b0a559783c8c5186fd816a4cee4d",
  "url": "https://osv.dev/vulnerability/CVE-2018-20421",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2018-20421",
    "summary": "Go Ethereum (aka geth) 1.8.19 allows attackers to cause a denial of service (memory consumption) by rewriting the length of a dynamic array in memory, and then writing data to a single memory location with a large index number, as demonstrated by use of \"assembly { mstore }\" followed by a \"c[0xC800000] = 0xFF\" assignment.",
    "evidence": "osv:CVE-2018-20421",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2018-20421",
      "aliases": [
        "CVE-2018-20421"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/ethereum/go-ethereum",
              "type": "GIT",
              "events": [
                {
                  "introduced": "dae82f098570e15d44584f0d7f350713f4774727"
                },
                {
                  "last_affected": "dae82f098570e15d44584f0d7f350713f4774727"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:ethereum:go_ethereum:1.8.19:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "1.8.19"
                      },
                      {
                        "last_affected": "1.8.19"
                      }
                    ],
                    "source": "CPE_STRING"
                  }
                ]
              }
            }
          ],
          "versions": [
            "1.8.19",
            "v1.8.19"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2018-20421.json"
          }
        }
      ],
      "modified": "2026-10-20T10:50:06.354665780Z",
      "provider": "osv",
      "references": [
        "https://github.com/ethereum/go-ethereum/issues/18289"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2018-20421",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 381280,
  "published_at": "2018-12-24T03:29:00.353+00:00"
}