id: PYSEC-2026-2085
published: "2026-07-04T02:16:23.603Z"
modified: "2026-07-09T10:36:41.968161Z"
aliases:
- CVE-2026-12252
- GHSA-9r6g-266r-89x4
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.
affected:
- package:
    name: nltk
    ecosystem: PyPI
    purl: pkg:pypi/nltk
  ranges:
  - type: ECOSYSTEM
    events:
    - introduced: "0"
    - fixed: 3.9.4
  versions:
  - "0.8"
  - "0.9"
  - 0.9.3
  - 0.9.4
  - 0.9.5
  - 0.9.6
  - 0.9.7
  - 0.9.8
  - 0.9.9
  - 2.0.1
  - 2.0.1rc1
  - 2.0.1rc2-git
  - 2.0.1rc3
  - 2.0.1rc4
  - 2.0.2
  - 2.0.3
  - 2.0.4
  - 2.0.5
  - 2.0b4
  - 2.0b5
  - 2.0b6
  - 2.0b7
  - 2.0b8
  - 2.0b9
  - 3.0.0
  - 3.0.0b1
  - 3.0.0b2
  - 3.0.1
  - 3.0.2
  - 3.0.3
  - 3.0.4
  - 3.0.5
  - "3.1"
  - "3.2"
  - 3.2.1
  - 3.2.2
  - 3.2.3
  - 3.2.4
  - 3.2.5
  - "3.3"
  - "3.4"
  - 3.4.1
  - 3.4.2
  - 3.4.3
  - 3.4.4
  - 3.4.5
  - "3.5"
  - 3.5b1
  - "3.6"
  - 3.6.1
  - 3.6.2
  - 3.6.3
  - 3.6.4
  - 3.6.5
  - 3.6.6
  - 3.6.7
  - "3.7"
  - "3.8"
  - 3.8.1
  - "3.9"
  - 3.9.1
  - 3.9.2
  - 3.9.3
  - 3.9b1
  ecosystem_specific: {}
references:
- type: EVIDENCE
  url: https://huntr.com/bounties/f5c93982-0cc9-4e2e-bb85-1b6ab29a2efb
- type: ADVISORY
  url: https://github.com/advisories/GHSA-9r6g-266r-89x4
severity:
- type: CVSS_V3
  score: CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H