HIGHVulnerability
Verified
Global

NVD HIGH: CVE-2025-71408 — NLTK (Natural Language Toolkit) before version 3.9.3 contains an eval injection ...

·Source: NIST NVD

Updated:

Executive Summary

NLTK (Natural Language Toolkit) before version 3.9.3 contains an eval injection vulnerability in the nltk.collocations module that allows an attacker who controls command-line arguments to execute arbitrary Python code. When collocations.py is invoked directly, the __main__ block passes command-line arguments directly to eval() as suffixes of BigramAssocMeasures without allowlist validation or san

Analysis

NLTK (Natural Language Toolkit) before version 3.9.3 contains an eval injection vulnerability in the nltk.collocations module that allows an attacker who controls command-line arguments to execute arbitrary Python code. When collocations.py is invoked directly, the __main__ block passes command-line arguments directly to eval() as suffixes of BigramAssocMeasures without allowlist validation or sanitization, enabling an attacker to supply a Python expression that escapes the intended attribute lookup and executes arbitrary code including OS commands via the os module. CVSS Score: 7.8. Published: 2026-07-24T22:16:50.063.

Indicators of Compromise (1)

CVE (1)
CVE-2025-71408
Source Attribution

Originally published by NIST NVD on Jul 24, 2026. Verified by: NIST.

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