Security advisory

{
  "id": "2e01f1f7d8a24047c65873b04a1c39c8a8a14d38ad3adac26c2d3000730282b6",
  "url": "https://osv.dev/vulnerability/CVE-2018-18920",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2018-18920",
    "summary": "Py-EVM v0.2.0-alpha.33 allows attackers to make a vm.execute_bytecode call that triggers computation._stack.values with '\"stack\": [100, 100, 0]' where b'\\x' was expected, resulting in an execution failure because of an invalid opcode. This is reportedly related to \"smart contracts can be executed indefinitely without gas being paid.\"",
    "evidence": "osv:CVE-2018-18920",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2018-18920",
      "aliases": [
        "CVE-2018-18920",
        "GHSA-vqgp-4jgj-5j64",
        "PYSEC-2018-155",
        "PYSEC-2018-96"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/ethereum/py-evm",
              "type": "GIT",
              "events": [
                {
                  "introduced": "a97dee05dba25cd743e5fc43c03add4dc5efd11c"
                },
                {
                  "last_affected": "a97dee05dba25cd743e5fc43c03add4dc5efd11c"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:ethereum:py-evm:0.2.0:alpha.33:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0.2.0-alpha\\.33"
                      },
                      {
                        "last_affected": "0.2.0-alpha\\.33"
                      }
                    ],
                    "source": "CPE_STRING"
                  }
                ]
              }
            }
          ],
          "versions": [
            "0.2.0-alpha\\.33",
            "v0.2.0-alpha.33"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2018-18920.json"
          }
        }
      ],
      "modified": "2026-10-20T10:51:34.628162772Z",
      "provider": "osv",
      "references": [
        "https://twitter.com/AlexanderFisher/status/1060923428641878019",
        "https://twitter.com/NettaLab/status/1060889400102383617",
        "https://www.reddit.com/r/ethereum/comments/9vkk2g/netta_labs_claim_to_have_found_a_vulnerability_in/e9d3wyx/",
        "https://github.com/ethereum/py-evm/issues/1448"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2018-18920",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 382589,
  "published_at": "2018-11-12T02:29:00.233+00:00"
}