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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2021-43854 Detail

Description

NLTK (Natural Language Toolkit) is a suite of open source Python modules, data sets, and tutorials supporting research and development in Natural Language Processing. Versions prior to 3.6.5 are vulnerable to regular expression denial of service (ReDoS) attacks. The vulnerability is present in PunktSentenceTokenizer, sent_tokenize and word_tokenize. Any users of this class, or these two functions, are vulnerable to the ReDoS attack. In short, a specifically crafted long input to any of these vulnerable functions will cause them to take a significant amount of execution time. If your program relies on any of the vulnerable functions for tokenizing unpredictable user input, then we would strongly recommend upgrading to a version of NLTK without the vulnerability. For users unable to upgrade the execution time can be bounded by limiting the maximum length of an input to any of the vulnerable functions. Our recommendation is to implement such a limit.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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Hyperlink Resource
https://github.com/nltk/nltk/commit/1405aad979c6b8080dbbc8e0858f89b2e3690341 Patch  Third Party Advisory 
https://github.com/nltk/nltk/issues/2866 Exploit  Issue Tracking  Patch  Third Party Advisory 
https://github.com/nltk/nltk/pull/2869 Exploit  Patch  Third Party Advisory 
https://github.com/nltk/nltk/security/advisories/GHSA-f8m6-h2c7-8h9x Exploit  Patch  Third Party Advisory 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-400 Uncontrolled Resource Consumption GitHub, Inc.  

Known Affected Software Configurations Switch to CPE 2.2

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Change History

2 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2021-43854
NVD Published Date:
12/23/2021
NVD Last Modified:
01/04/2022
Source:
GitHub, Inc.