CVE-2026-0848 (GCVE-0-2026-0848)

Vulnerability from cvelistv5 – Published: 2026-03-05 20:48 – Updated: 2026-03-06 16:31
VLAI?
Title
Arbitrary Code Execution in NLTK StanfordSegmenter via Untrusted JAR Loading
Summary
NLTK versions <=3.9.2 are vulnerable to arbitrary code execution due to improper input validation in the StanfordSegmenter module. The module dynamically loads external Java .jar files without verification or sandboxing. An attacker can supply or replace the JAR file, enabling the execution of arbitrary Java bytecode at import time. This vulnerability can be exploited through methods such as model poisoning, MITM attacks, or dependency poisoning, leading to remote code execution. The issue arises from the direct execution of the JAR file via subprocess with unvalidated classpath input, allowing malicious classes to execute when loaded by the JVM.
Severity ?
10 (Critical)
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
CWE
  • CWE-20 - Improper Input Validation
Assigner
References
Impacted products
Vendor Product Version
nltk nltk/nltk Affected: unspecified , ≤ latest (custom)
Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-0848",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-03-06T16:30:57.313646Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-03-06T16:31:01.105Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://huntr.com/bounties/08b109bb-ac24-403f-9422-1c246ce60202"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "nltk/nltk",
          "vendor": "nltk",
          "versions": [
            {
              "lessThanOrEqual": "latest",
              "status": "affected",
              "version": "unspecified",
              "versionType": "custom"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "NLTK versions \u003c=3.9.2 are vulnerable to arbitrary code execution due to improper input validation in the StanfordSegmenter module. The module dynamically loads external Java .jar files without verification or sandboxing. An attacker can supply or replace the JAR file, enabling the execution of arbitrary Java bytecode at import time. This vulnerability can be exploited through methods such as model poisoning, MITM attacks, or dependency poisoning, leading to remote code execution. The issue arises from the direct execution of the JAR file via subprocess with unvalidated classpath input, allowing malicious classes to execute when loaded by the JVM."
        }
      ],
      "metrics": [
        {
          "cvssV3_0": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 10,
            "baseSeverity": "CRITICAL",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
            "version": "3.0"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-20",
              "description": "CWE-20 Improper Input Validation",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-03-05T20:48:05.364Z",
        "orgId": "c09c270a-b464-47c1-9133-acb35b22c19a",
        "shortName": "@huntr_ai"
      },
      "references": [
        {
          "url": "https://huntr.com/bounties/08b109bb-ac24-403f-9422-1c246ce60202"
        }
      ],
      "source": {
        "advisory": "08b109bb-ac24-403f-9422-1c246ce60202",
        "discovery": "EXTERNAL"
      },
      "title": "Arbitrary Code Execution in NLTK StanfordSegmenter via Untrusted JAR Loading"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "c09c270a-b464-47c1-9133-acb35b22c19a",
    "assignerShortName": "@huntr_ai",
    "cveId": "CVE-2026-0848",
    "datePublished": "2026-03-05T20:48:05.364Z",
    "dateReserved": "2026-01-10T23:59:44.115Z",
    "dateUpdated": "2026-03-06T16:31:01.105Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-0848",
      "date": "2026-04-14",
      "epss": "0.00523",
      "percentile": "0.66928"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-0848\",\"sourceIdentifier\":\"security@huntr.dev\",\"published\":\"2026-03-05T21:16:14.263\",\"lastModified\":\"2026-03-09T13:36:08.413\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"NLTK versions \u003c=3.9.2 are vulnerable to arbitrary code execution due to improper input validation in the StanfordSegmenter module. The module dynamically loads external Java .jar files without verification or sandboxing. An attacker can supply or replace the JAR file, enabling the execution of arbitrary Java bytecode at import time. This vulnerability can be exploited through methods such as model poisoning, MITM attacks, or dependency poisoning, leading to remote code execution. The issue arises from the direct execution of the JAR file via subprocess with unvalidated classpath input, allowing malicious classes to execute when loaded by the JVM.\"},{\"lang\":\"es\",\"value\":\"Las versiones de NLTK \u0026lt;=3.9.2 son vulnerables a ejecuci\u00f3n de c\u00f3digo arbitrario debido a una validaci\u00f3n de entrada inadecuada en el m\u00f3dulo StanfordSegmenter. El m\u00f3dulo carga din\u00e1micamente archivos .jar de Java externos sin verificaci\u00f3n ni sandboxing. Un atacante puede suministrar o reemplazar el archivo JAR, permitiendo la ejecuci\u00f3n de bytecode Java arbitrario en el momento de la importaci\u00f3n. Esta vulnerabilidad puede ser explotada a trav\u00e9s de m\u00e9todos como el envenenamiento de modelos, ataques MitM o el envenenamiento de dependencias, lo que lleva a ejecuci\u00f3n remota de c\u00f3digo. El problema surge de la ejecuci\u00f3n directa del archivo JAR a trav\u00e9s de un subproceso con entrada de classpath no validada, permitiendo que clases maliciosas se ejecuten cuando son cargadas por la JVM.\"}],\"metrics\":{\"cvssMetricV30\":[{\"source\":\"security@huntr.dev\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.0\",\"vectorString\":\"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H\",\"baseScore\":10.0,\"baseSeverity\":\"CRITICAL\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"CHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":6.0}]},\"weaknesses\":[{\"source\":\"security@huntr.dev\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-20\"}]}],\"references\":[{\"url\":\"https://huntr.com/bounties/08b109bb-ac24-403f-9422-1c246ce60202\",\"source\":\"security@huntr.dev\"},{\"url\":\"https://huntr.com/bounties/08b109bb-ac24-403f-9422-1c246ce60202\",\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\"}]}}",
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-0848\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"poc\"}, {\"Automatable\": \"yes\"}, {\"Technical Impact\": \"total\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-03-06T16:30:57.313646Z\"}}}], \"references\": [{\"url\": \"https://huntr.com/bounties/08b109bb-ac24-403f-9422-1c246ce60202\", \"tags\": [\"exploit\"]}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-03-06T16:30:50.393Z\"}}], \"cna\": {\"title\": \"Arbitrary Code Execution in NLTK StanfordSegmenter via Untrusted JAR Loading\", \"source\": {\"advisory\": \"08b109bb-ac24-403f-9422-1c246ce60202\", \"discovery\": \"EXTERNAL\"}, \"metrics\": [{\"cvssV3_0\": {\"scope\": \"CHANGED\", \"version\": \"3.0\", \"baseScore\": 10, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"CRITICAL\", \"vectorString\": \"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H\", \"integrityImpact\": \"HIGH\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"HIGH\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"HIGH\"}}], \"affected\": [{\"vendor\": \"nltk\", \"product\": \"nltk/nltk\", \"versions\": [{\"status\": \"affected\", \"version\": \"unspecified\", \"versionType\": \"custom\", \"lessThanOrEqual\": \"latest\"}]}], \"references\": [{\"url\": \"https://huntr.com/bounties/08b109bb-ac24-403f-9422-1c246ce60202\"}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"NLTK versions \u003c=3.9.2 are vulnerable to arbitrary code execution due to improper input validation in the StanfordSegmenter module. The module dynamically loads external Java .jar files without verification or sandboxing. An attacker can supply or replace the JAR file, enabling the execution of arbitrary Java bytecode at import time. This vulnerability can be exploited through methods such as model poisoning, MITM attacks, or dependency poisoning, leading to remote code execution. The issue arises from the direct execution of the JAR file via subprocess with unvalidated classpath input, allowing malicious classes to execute when loaded by the JVM.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-20\", \"description\": \"CWE-20 Improper Input Validation\"}]}], \"providerMetadata\": {\"orgId\": \"c09c270a-b464-47c1-9133-acb35b22c19a\", \"shortName\": \"@huntr_ai\", \"dateUpdated\": \"2026-03-05T20:48:05.364Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-0848\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-03-06T16:31:01.105Z\", \"dateReserved\": \"2026-01-10T23:59:44.115Z\", \"assignerOrgId\": \"c09c270a-b464-47c1-9133-acb35b22c19a\", \"datePublished\": \"2026-03-05T20:48:05.364Z\", \"assignerShortName\": \"@huntr_ai\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.