Malicious code in @coopeuch/button (npm)

{
  "id": "ba5efb55372cc7d35a9def7f99b3b30a14da3183914b8a072bbb91cff1e49868",
  "url": "https://osv.dev/vulnerability/MAL-2026-17759",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Malicious code in @coopeuch/button (npm)",
    "summary": "--- _-= Per source details. Do not edit below this line.=-_ ## Source: amazon-inspector (ee1a3bb0818d46a9c83659ed32f8ab209477970658d5f6f8241a12c96d137c98) The package's postinstall lifecycle script (postinstall.js) runs automatically on `npm install` and harvests installer host identifiers — hostname, username, uid/gid, home directory, non-internal network interfaces with MAC addresses and CIDRs, configured DNS servers, reverse-DNS internal FQDN, CPU/memory, the consumer package name/version/path, CI markers, npm_config_* values, and container runtime indicators — then POSTs the JSON report over HTTPS to the hardcoded host collector.oob.s4yhii.com at /_npm-poc/beacon and issues a DNS lookup for a label-prefixed subdomain of oob.s4yhii.com as an out-of-band beacon. The destination is not the installer's own infrastructure and is not caller-configurable. The `@coopeuch` scope combined with the 1.999.999 version has the shape of dependency-confusion targeting of a specific organization's internal namespace, in which `npm install` resolves this public package in place of an intended internal one and emits the fingerprint to the author's collector. ## Source: ghsa-malware (2acd60fae59edef47c863b5bb4874afbdfc59b1360bb5feec23847efa2da477c) Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full contro",
    "evidence": "osv:MAL-2026-17759",
    "products": [
      {
        "name": {
          "value": "@coopeuch/button",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "1.999.999",
            "evidence": "/affected/0/versions"
          }
        ]
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "MAL-2026-17759",
      "aliases": [
        "GHSA-55qj-2wwm-x5v6",
        "MAL-2026-17759"
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "@coopeuch/button",
            "purl": "pkg:npm/%40coopeuch/button",
            "ecosystem": "npm"
          },
          "versions": [
            "1.999.999"
          ],
          "database_specific": {
            "cwes": [
              {
                "name": "Embedded Malicious Code",
                "cweId": "CWE-506",
                "description": "The product contains code that appears to be malicious in nature."
              },
              {
                "name": "Embedded Malicious Code",
                "cweId": "CWE-506",
                "description": "The product contains code that appears to be malicious in nature."
              }
            ],
            "source": "https://github.com/ossf/malicious-packages/blob/main/osv/malicious/npm/@coopeuch/button/MAL-2026-17759.json",
            "indicators": {
              "evidence_files": [
                {
                  "path": "postinstall.js",
                  "tlsh": "0ae1fa6a05fe1132226235f4694b50156776d1633504fbf4b9dd8280afcf0ba42bb7ed",
                  "sha256": "c859191e9d7e04d59b5d2f566799feb31594a68573350bd17661be469e8663ef"
                }
              ],
              "package_integrity": [
                {
                  "hashes": {
                    "sha1": "61f39ae0da10a23d16e2de630ae0d5ce74568d47",
                    "sha512_sri": "sha512-SCbYYuiCW0bOdd4UWw/wU3O5OQlXaFmEYuQTFJjW1n1JEATG2c8uoSp7nnBbrNteRPcxjtIJlrAlGR2O90WjAA=="
                  },
                  "filename": "button-1.999.999.tgz"
                }
              ]
            }
          }
        }
      ],
      "modified": "2026-10-12T19:30:04.560279400Z",
      "provider": "osv",
      "references": [
        "https://www.npmjs.com/package/@coopeuch/button/v/1.999.999",
        "https://github.com/advisories/GHSA-55qj-2wwm-x5v6"
      ],
      "provider_metadata": {
        "malicious-packages-origins": [
          {
            "id": "IN-MAL-2026-021386",
            "sha256": "ee1a3bb0818d46a9c83659ed32f8ab209477970658d5f6f8241a12c96d137c98",
            "source": "amazon-inspector",
            "versions": [
              "1.999.999"
            ],
            "import_time": "2026-10-11T14:18:01.403405383Z",
            "modified_time": "2026-10-11T13:51:41Z"
          },
          {
            "id": "GHSA-55qj-2wwm-x5v6",
            "ranges": [
              {
                "type": "SEMVER",
                "events": [
                  {
                    "introduced": "0"
                  }
                ]
              }
            ],
            "sha256": "2acd60fae59edef47c863b5bb4874afbdfc59b1360bb5feec23847efa2da477c",
            "source": "ghsa-malware",
            "import_time": "2026-10-12T19:24:46.897577987Z",
            "modified_time": "2026-10-12T19:07:14Z"
          }
        ]
      }
    },
    "related_cves": [],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 306739,
  "published_at": "2026-10-11T13:51:41+00:00"
}