Security advisory

{
  "id": "c6c0367ee47b415345a6c45faea5be77a65097ddf33cdf3f4f53d4f0b4eddf19",
  "url": "https://osv.dev/vulnerability/CVE-2021-43568",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-43568",
    "summary": "The verify function in the Stark Bank Elixir ECDSA library (ecdsa-elixir) 1.0.0 fails to check that the signature is non-zero, which allows attackers to forge signatures on arbitrary messages.",
    "evidence": "osv:CVE-2021-43568",
    "products": [],
    "severity": "critical",
    "structured": {
      "id": "CVE-2021-43568",
      "aliases": [
        "CVE-2021-43568",
        "GHSA-xx36-6rv4-gj8r"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/starkbank/ecdsa-elixir",
              "type": "GIT",
              "events": [
                {
                  "introduced": "54b4472e4f2831cc054d63761ce16e0af1aa10ca"
                },
                {
                  "last_affected": "54b4472e4f2831cc054d63761ce16e0af1aa10ca"
                },
                {
                  "fixed": "5c3152e95dbea47f92185fdab8be4030d9b86c2c"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:starkbank:elixir_ecdsa:1.0.0:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "1.0.0"
                      },
                      {
                        "last_affected": "1.0.0"
                      }
                    ],
                    "source": "CPE_STRING"
                  },
                  {
                    "range": [
                      {
                        "fixed": "5c3152e95dbea47f92185fdab8be4030d9b86c2c"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v1.0.1"
                  }
                ]
              }
            }
          ],
          "versions": [
            "1.0.0",
            "v1.0.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-43568.json"
          }
        }
      ],
      "modified": "2026-10-20T10:54:09.019986592Z",
      "provider": "osv",
      "references": [
        "https://github.com/starkbank/ecdsa-elixir/releases/tag/v1.0.1",
        "https://research.nccgroup.com/2021/11/08/technical-advisory-arbitrary-signature-forgery-in-stark-bank-ecdsa-libraries/"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2021-43568",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 384901,
  "published_at": "2021-11-09T22:15:07.553+00:00"
}