Vulnerability-Lookup

UBUNTU-CVE-2026-12252 (CVE-2026-12252)

Vulnerability from osv_ubuntu – Published: 2026-07-04 02:16 – Updated: 2026-07-09 15:15 – Source website

Details

In nltk/nltk versions 3.9.3 and earlier, five Stanford interface classes (StanfordPOSTagger, StanfordNERTagger, StanfordParser, StanfordDependencyParser, and StanfordNeuralDependencyParser) are vulnerable to untrusted JAR code execution. These classes accept user-controllable JAR paths and execute them via the java() function, which invokes subprocess.Popen() without integrity verification. This vulnerability is identical to CVE-2026-0848, which was fixed for StanfordSegmenter by adding SHA256 verification. However, the fix was not applied to these additional classes, leaving them susceptible to arbitrary code execution when loading untrusted JAR files.

Severity

7.8 (High)


                    
                      CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-12252	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-12252	REPORT
	https://huntr.com/bounties/f5c93982-0cc9-4e2e-bb8…	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "python-nltk",
            "binary_version": "2.0~b9-0ubuntu4.1~esm6"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:14.04:LTS",
        "name": "nltk",
        "purl": "pkg:deb/ubuntu/nltk@2.0~b9-0ubuntu4.1~esm6?arch=source\u0026distro=esm-infra-legacy/trusty"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.0~b9-0ubuntu4",
        "2.0~b9-0ubuntu4.1~esm2",
        "2.0~b9-0ubuntu4.1~esm4",
        "2.0~b9-0ubuntu4.1~esm5",
        "2.0~b9-0ubuntu4.1~esm6"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "python-nltk",
            "binary_version": "3.1-1ubuntu0.1+esm4"
          },
          {
            "binary_name": "python3-nltk",
            "binary_version": "3.1-1ubuntu0.1+esm4"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:16.04:LTS",
        "name": "nltk",
        "purl": "pkg:deb/ubuntu/nltk@3.1-1ubuntu0.1+esm4?arch=source\u0026distro=esm-apps-legacy/xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.0.4-1",
        "3.0.5-1",
        "3.1-1",
        "3.1-1ubuntu0.1",
        "3.1-1ubuntu0.1+esm1",
        "3.1-1ubuntu0.1+esm2",
        "3.1-1ubuntu0.1+esm3",
        "3.1-1ubuntu0.1+esm4"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "python-nltk",
            "binary_version": "3.2.5-1ubuntu0.1+esm4"
          },
          {
            "binary_name": "python3-nltk",
            "binary_version": "3.2.5-1ubuntu0.1+esm4"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "nltk",
        "purl": "pkg:deb/ubuntu/nltk@3.2.5-1ubuntu0.1+esm4?arch=source\u0026distro=esm-apps/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.2.4-1",
        "3.2.5-1",
        "3.2.5-1ubuntu0.1",
        "3.2.5-1ubuntu0.1+esm1",
        "3.2.5-1ubuntu0.1+esm2",
        "3.2.5-1ubuntu0.1+esm3",
        "3.2.5-1ubuntu0.1+esm4"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "python3-nltk",
            "binary_version": "3.4.5-2ubuntu0.1~esm4"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:20.04:LTS",
        "name": "nltk",
        "purl": "pkg:deb/ubuntu/nltk@3.4.5-2ubuntu0.1~esm4?arch=source\u0026distro=esm-apps/focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.4.5-1",
        "3.4.5-2",
        "3.4.5-2ubuntu0.1~esm1",
        "3.4.5-2ubuntu0.1~esm2",
        "3.4.5-2ubuntu0.1~esm3",
        "3.4.5-2ubuntu0.1~esm4"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "python3-nltk",
            "binary_version": "3.7-1ubuntu0.1~esm2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:22.04:LTS",
        "name": "nltk",
        "purl": "pkg:deb/ubuntu/nltk@3.7-1ubuntu0.1~esm2?arch=source\u0026distro=esm-apps/jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.5-1",
        "3.6.5-1",
        "3.6.7-1",
        "3.7-1",
        "3.7-1ubuntu0.1~esm1",
        "3.7-1ubuntu0.1~esm2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "python3-nltk",
            "binary_version": "3.8.1-1ubuntu0.1~esm2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:24.04:LTS",
        "name": "nltk",
        "purl": "pkg:deb/ubuntu/nltk@3.8.1-1ubuntu0.1~esm2?arch=source\u0026distro=esm-apps/noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.8.1-1",
        "3.8.1-1ubuntu0.1~esm1",
        "3.8.1-1ubuntu0.1~esm2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "python3-nltk",
            "binary_version": "3.9.1-2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "nltk",
        "purl": "pkg:deb/ubuntu/nltk@3.9.1-2?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.9.1-2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "python3-nltk",
            "binary_version": "3.9.2-1ubuntu0.1~esm2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:26.04:LTS",
        "name": "nltk",
        "purl": "pkg:deb/ubuntu/nltk@3.9.2-1ubuntu0.1~esm2?arch=source\u0026distro=esm-apps/resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.9.1-2",
        "3.9.1-2build1",
        "3.9.2-1",
        "3.9.2-1ubuntu0.1~esm1",
        "3.9.2-1ubuntu0.1~esm2"
      ]
    }
  ],
  "aliases": [],
  "details": "In nltk/nltk versions 3.9.3 and earlier, five Stanford interface classes (StanfordPOSTagger, StanfordNERTagger, StanfordParser, StanfordDependencyParser, and StanfordNeuralDependencyParser) are vulnerable to untrusted JAR code execution. These classes accept user-controllable JAR paths and execute them via the `java()` function, which invokes `subprocess.Popen()` without integrity verification. This vulnerability is identical to CVE-2026-0848, which was fixed for StanfordSegmenter by adding SHA256 verification. However, the fix was not applied to these additional classes, leaving them susceptible to arbitrary code execution when loading untrusted JAR files.",
  "id": "UBUNTU-CVE-2026-12252",
  "modified": "2026-07-09T15:15:45Z",
  "published": "2026-07-04T02:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-12252"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-12252"
    },
    {
      "type": "REPORT",
      "url": "https://huntr.com/bounties/f5c93982-0cc9-4e2e-bb85-1b6ab29a2efb"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-12252"
  ]
}

CVE-2026-12252 (GCVE-0-2026-12252)

Vulnerability from cvelistv5 – Published: 2026-07-04 00:58 – Updated: 2026-07-06 18:33

Title

Untrusted JAR Code Execution in Multiple Stanford Interface Classes in nltk/nltk

Summary

In nltk/nltk versions 3.9.3 and earlier, five Stanford interface classes (StanfordPOSTagger, StanfordNERTagger, StanfordParser, StanfordDependencyParser, and StanfordNeuralDependencyParser) are vulnerable to untrusted JAR code execution. These classes accept user-controllable JAR paths and execute them via the `java()` function, which invokes `subprocess.Popen()` without integrity verification. This vulnerability is identical to CVE-2026-0848, which was fixed for StanfordSegmenter by adding SHA256 verification. However, the fix was not applied to these additional classes, leaving them susceptible to arbitrary code execution when loading untrusted JAR files.

Severity

7.8 (High)


                        
                          CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

SSVC

Exploitation: poc Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-07-06 18:32 UTC

CWE

CWE-94 - Improper Control of Generation of Code

Assigner

@huntr_ai mitre root

References

1 reference

URL	Tags
https://huntr.com/bounties/f5c93982-0cc9-4e2e-bb8…

Impacted products

1 product

Vendor	Product	Version
nltk	nltk/nltk	Affected: unspecified , ≤ latest (custom)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-12252",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-06T18:32:42.979501Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-07-06T18:33:11.411Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://huntr.com/bounties/f5c93982-0cc9-4e2e-bb85-1b6ab29a2efb"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "nltk/nltk",
          "vendor": "nltk",
          "versions": [
            {
              "lessThanOrEqual": "latest",
              "status": "affected",
              "version": "unspecified",
              "versionType": "custom"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In nltk/nltk versions 3.9.3 and earlier, five Stanford interface classes (StanfordPOSTagger, StanfordNERTagger, StanfordParser, StanfordDependencyParser, and StanfordNeuralDependencyParser) are vulnerable to untrusted JAR code execution. These classes accept user-controllable JAR paths and execute them via the `java()` function, which invokes `subprocess.Popen()` without integrity verification. This vulnerability is identical to CVE-2026-0848, which was fixed for StanfordSegmenter by adding SHA256 verification. However, the fix was not applied to these additional classes, leaving them susceptible to arbitrary code execution when loading untrusted JAR files."
        }
      ],
      "metrics": [
        {
          "cvssV3_0": {
            "attackComplexity": "LOW",
            "attackVector": "LOCAL",
            "availabilityImpact": "HIGH",
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
            "version": "3.0"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-94",
              "description": "CWE-94 Improper Control of Generation of Code",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-04T00:58:58.930Z",
        "orgId": "c09c270a-b464-47c1-9133-acb35b22c19a",
        "shortName": "@huntr_ai"
      },
      "references": [
        {
          "url": "https://huntr.com/bounties/f5c93982-0cc9-4e2e-bb85-1b6ab29a2efb"
        }
      ],
      "source": {
        "advisory": "f5c93982-0cc9-4e2e-bb85-1b6ab29a2efb",
        "discovery": "EXTERNAL"
      },
      "title": "Untrusted JAR Code Execution in Multiple Stanford Interface Classes in nltk/nltk"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "c09c270a-b464-47c1-9133-acb35b22c19a",
    "assignerShortName": "@huntr_ai",
    "cveId": "CVE-2026-12252",
    "datePublished": "2026-07-04T00:58:58.930Z",
    "dateReserved": "2026-06-15T08:33:00.274Z",
    "dateUpdated": "2026-07-06T18:33:11.411Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

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.
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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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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Action not permitted

UBUNTU-CVE-2026-12252 (CVE-2026-12252)

CVE-2026-12252 (GCVE-0-2026-12252)

Tags

Sightings

Nomenclature

Related by attack behaviour