PyPI: nltk

CVE-2021-3842

Safety vulnerability ID: SFTY-20220104-12451

Safety legacy ID: pyup.io-54703

Nltk before 3.6.6 is vulnerable to Inefficient Regular Expression Complexity.

Created at: Nov 5, 2025Updated at: Nov 5, 2025

Overview

NLTK Vulnerable to REDoS

Advisory

Nltk before 3.6.6 is vulnerable to Inefficient Regular Expression Complexity.

Affected Package

Affecting nltk package, versions
>=0,<3.6.6

Also affects

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How to Fix

Upgrade
nltk
to
3.6.6
or higher.

Mitigation and Workarounds

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Vulnerable Functions

Functions linked to known vulnerabilities.

Vulnerable function data is available for Enterprise customers

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Safety

Verified by Safety

Our Cybersecurity Intelligence Team reviewed this vulnerability. We combine public data with our own research to find issues not yet reported to public sources.

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