Inefficient Regular Expression Complexity Affecting nltk package, versions <3.10.0-1


Severity

Recommended
0.0
high
0
10

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Threat Intelligence

EPSS
0.49% (41st percentile)

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  • Snyk IDSNYK-DEBIANUNSTABLE-NLTK-19271317
  • published27 Aug 2026
  • disclosed26 Aug 2026

Introduced: 26 Aug 2026

NewCVE-2026-80205  (opens in a new tab)
CWE-1333  (opens in a new tab)

How to fix?

Upgrade Debian:unstable nltk to version 3.10.0-1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream nltk package and not the nltk package as distributed by Debian. See How to fix? for Debian:unstable relevant fixed versions and status.

NLTK versions before 3.10.0 contain a regular expression denial of service vulnerability in Text.findall() and TokenSearcher.findall() methods that accept user-supplied regular expressions without validation or timeout. Attackers can supply crafted regex patterns that cause catastrophic backtracking, resulting in indefinite CPU saturation and denial of service to all users of the Python process.

CVSS Base Scores

version 3.1