NLTK through 3.10.3 Path Traversal via WekaClassifier Model Path

{
  "id": "88d936f86a5dc69624ab1abe9a744838458d1f77230d0bad506cd610079a5f5d",
  "url": "https://www.cve.org/CVERecord?id=CVE-2026-109956",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "NLTK through 3.10.3 Path Traversal via WekaClassifier Model Path",
    "summary": "NLTK through 3.10.3 contains a path traversal vulnerability in WekaClassifier that allows attackers to bypass nltk.pathsec containment by supplying unvalidated model paths. Attackers controlling the model_filename or model argument can make the weka JVM write files via -d or probe files via -l outside allowed data roots.",
    "evidence": "cve:CVE-2026-109956",
    "products": [
      {
        "name": {
          "value": "nltk",
          "evidence": "/containers/cna/affected/0/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-109956",
      "aliases": [
        "CVE-2026-109956"
      ],
      "metrics": [
        {
          "format": "CVSS",
          "cvssV4_0": {
            "version": "4.0",
            "baseScore": 8.3,
            "attackVector": "NETWORK",
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:L/SC:N/SI:N/SA:N",
            "userInteraction": "NONE",
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "privilegesRequired": "NONE",
            "subIntegrityImpact": "NONE",
            "vulnIntegrityImpact": "HIGH",
            "subAvailabilityImpact": "NONE",
            "vulnAvailabilityImpact": "LOW",
            "subConfidentialityImpact": "NONE",
            "vulnConfidentialityImpact": "LOW"
          }
        },
        {
          "format": "CVSS",
          "cvssV3_1": {
            "scope": "UNCHANGED",
            "version": "3.1",
            "baseScore": 7,
            "attackVector": "NETWORK",
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:L",
            "integrityImpact": "HIGH",
            "userInteraction": "NONE",
            "attackComplexity": "HIGH",
            "availabilityImpact": "LOW",
            "privilegesRequired": "NONE",
            "confidentialityImpact": "LOW"
          }
        }
      ],
      "affected": [
        {
          "vendor": "nltk",
          "product": "nltk",
          "versions": [
            {
              "status": "affected",
              "version": "0",
              "versionType": "semver",
              "lessThanOrEqual": "3.10.3"
            }
          ],
          "packageURL": "pkg:pypi/nltk",
          "defaultStatus": "unaffected"
        }
      ],
      "modified": "2026-10-26T19:46:30.241Z",
      "provider": "cve",
      "references": [
        "https://github.com/nltk/nltk/security/advisories/GHSA-j456-xh4h-cpf2",
        "https://www.vulncheck.com/advisories/nltk-through-3.10.3-path-traversal-via-wekaclassifier-model-path"
      ],
      "provider_metadata": {
        "adp": [
          {
            "title": "CISA ADP Vulnrichment",
            "metrics": [
              {
                "other": {
                  "type": "ssvc",
                  "content": {
                    "id": "CVE-2026-109956",
                    "role": "CISA Coordinator",
                    "options": [
                      {
                        "Exploitation": "poc"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "version": "2.0.3",
                    "timestamp": "2026-10-26T19:46:23.846442Z"
                  }
                }
              }
            ],
            "references": [
              {
                "url": "https://github.com/nltk/nltk/security/advisories/GHSA-j456-xh4h-cpf2",
                "tags": [
                  "exploit"
                ]
              }
            ],
            "providerMetadata": {
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP",
              "dateUpdated": "2026-10-26T19:46:30.241Z"
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        ],
        "cna": {
          "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
          "shortName": "VulnCheck",
          "dateUpdated": "2026-10-13T13:27:20.244Z"
        }
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    },
    "related_cves": [
      {
        "value": "CVE-2026-109956",
        "evidence": "/cveMetadata/cveId"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/containers/cna/metrics"
  },
  "source_id": "core-cve",
  "document_id": 338274,
  "published_at": "2026-10-13T13:27:20.244+00:00"
}