ETK-2026-551Zero's internal tracking ID, independent of the CVE number.

{
  "etk_id": "ETK-2026-551",
  "cve_id": null,
  "display_id": "ETK-2026-551",
  "ghsa_id": "GHSA-9fr5-46w5-5f9r",
  "euvd_id": null,
  "status": "published",
  "anchor_state": "awaiting_cve",
  "title": "Algorithmic denial of service in btclib tapscript validation",
  "summary": "btclib versions before 2026.10.4 can consume excessive CPU while validating certain valid P2TR script-path transactions. An attacker can delay a service that validates transactions or blocks from untrusted sources, including peer-provided data.",
  "mitigation": "Upgrade btclib to version 2026.10.4 or later. Until upgrade, restrict untrusted transaction validation and apply resource limits where your deployment permits.",
  "vendor": "pip",
  "product": "pip:btclib",
  "affected": [
    {
      "affected_notes": [],
      "affected_ranges": [
        "<= 2026.10.3"
      ],
      "ecosystem": "pip",
      "fixed_versions": [
        "2026.10.4"
      ],
      "package_name": "btclib",
      "purl": "pkg:pypi/btclib"
    }
  ],
  "cwes": [
    407
  ],
  "cvss_score": 7.5,
  "cvss_src": "cna_vendor",
  "cvss_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
  "epss_score": null,
  "epss_percentile": null,
  "epss_asof": null,
  "automation": "deterministic",
  "check": false,
  "check_confidence_basis": null,
  "exploit": false,
  "pipeline_minutes": 13.015074816666667,
  "t0_at": null,
  "signals": {
    "trigger_signal": {
      "at": "2026-10-03T22:17:01+00:00",
      "days": -17.895143924583333,
      "is_lower_bound": true,
      "measured_at": "2026-10-21T19:46:01.458024+00:00",
      "url": "https://github.com/btclib-org/btclib/security/advisories/GHSA-9fr5-46w5-5f9r"
    }
  }
}