CVE-2026-80205

NLTK before 3.10.0 ReDoS via Text.findall() unvalidated regex

Published Aug 26, 2026 CVSS 4.0 · 8.7 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-rrv8-h7p8-rx55 NLTK: ReDoS in nltk.text.Text.findall() via unvalidated user-supplied regular expressions
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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.
Title NLTK before 3.10.0 ReDoS via Text.findall() unvalidated regex
First Time appeared Nltk
Nltk nltk
Weaknesses CWE-1333
CPEs cpe:2.3:a:nltk:nltk:*:*:*:*:*:*:*:*
Vendors & Products Nltk
Nltk nltk
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Sep 1, 2026, 10:06 PM
Reserved
Aug 25, 2026, 11:15 PM
Status
Modified
Published
Aug 26, 2026, 11:16 AM
Modified
Sep 3, 2026, 5:15 AM
Severity
Important
Public date
Aug 26, 2026, 10:28 AM