---
id: CVE-2026-12252
title: >-
  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.…
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.…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'
cwe:
  - CWE-94
published: '2026-07-04'
updated: '2026-07-04'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-12252'
references:
  - url: 'https://huntr.com/bounties/f5c93982-0cc9-4e2e-bb85-1b6ab29a2efb'
    label: security@huntr.dev
tags:
  - nvd
epss: 0.00235
epssPercentile: 0.12903
ingestedAt: '2026-07-04T21:57:46.862Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.