---
id: GHSA-2rrw-hpqm-36pv
title: >-
  Duplicate Advisory:  ReDoS in nltk.text.Text.findall() via unvalidated
  user-supplied regular expressions
summary: >-
  Duplicate Advisory:  ReDoS in nltk.text.Text.findall() via unvalidated
  user-supplied regular expressions
severity: high
cvss: 7.5
cwe:
  - CWE-1333
vendor: nltk
product: nltk
ecosystem: pip
affected:
  - nltk <= 3.9.4
published: '2026-08-26'
updated: '2026-09-08'
sourceUpdated: '2026-09-08T20:28:00Z'
source: GHSA
sourceUrl: 'https://github.com/advisories/GHSA-2rrw-hpqm-36pv'
references:
  - url: 'https://github.com/nltk/nltk/security/advisories/GHSA-rrv8-h7p8-rx55'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-80205'
  - url: >-
      https://www.vulncheck.com/advisories/nltk-before-3.10.0-redos-via-text-findall-unvalidated-regex
  - url: 'http://www.openwall.com/lists/oss-security/2026/09/01/3'
  - url: 'https://github.com/advisories/GHSA-2rrw-hpqm-36pv'
tags:
  - ghsa
  - pip
ingestedAt: '2026-09-08T21:11:12.322Z'
---

## Overview

## Duplicate Advisory

This advisory has been withdrawn because it is a duplicate of GHSA-rrv8-h7p8-rx55. This link is maintained to preserve external references.

## Original Description
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.

## Affected packages

- `nltk <= 3.9.4`

## Remediation

Refer to the advisory for the patched release.