CVE-2026-126298

{
  "etk_id": "ETK-2026-4438",
  "cve_id": "CVE-2026-126298",
  "display_id": "CVE-2026-126298",
  "ghsa_id": "GHSA-6665-2vj3-h76r",
  "euvd_id": "EUVD-2026-125223",
  "status": "published",
  "anchor_state": "anchored",
  "title": "Quadratic CPU denial of service in NLTK tree normalization",
  "summary": "NLTK versions through 3.10.3 can consume excessive CPU while normalizing parse trees to Chomsky Normal Form. An attacker can cause processing delays or block a worker by supplying a tree with a very large number of children, if the application accepts attacker-influenced trees and invokes the default normalization path.",
  "mitigation": "Upgrade nltk to version 3.10.4 or later. Until upgrading, reject or cap unusually wide untrusted trees before normalization and isolate the work with CPU or time limits.",
  "vendor": "pip",
  "product": "nltk",
  "affected": [
    {
      "affected_notes": [],
      "affected_ranges": [
        "<= 3.10.3"
      ],
      "ecosystem": "pip",
      "fixed_versions": [
        "3.10.4"
      ],
      "package_name": "nltk",
      "purl": "pkg:pypi/nltk"
    }
  ],
  "cwes": null,
  "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": "contextual",
  "check": true,
  "check_confidence_basis": "assessed",
  "exploit": false,
  "pipeline_minutes": 8.420537833333333,
  "t0_at": "2026-11-13T09:36:27.213000+00:00",
  "signals": {
    "check": {
      "at": "2026-11-14T00:20:23.325427+00:00",
      "days": 0.6138438938310186,
      "is_lower_bound": false,
      "measured_at": "2026-11-13T09:36:27.213000+00:00",
      "url": null
    },
    "public_poc": {
      "at": "2026-11-14T00:07:59+00:00",
      "days": 0.6052290162037037,
      "is_lower_bound": false,
      "measured_at": "2026-11-13T09:36:27.213000+00:00",
      "url": "https://github.com/advisories/GHSA-r53h-rw34-8h97"
    },
    "trigger_signal": {
      "at": "2026-11-13T09:36:27.213000+00:00",
      "days": 0,
      "is_lower_bound": false,
      "measured_at": "2026-11-13T09:36:27.213000+00:00",
      "url": "https://github.com/advisories/GHSA-r53h-rw34-8h97"
    }
  }
}