CVE-2026-81723

Low

Description

NLTK versions before 3.10.3 contain a quadratic CPU exhaustion vulnerability in XMLCorpusView._read_xml_fragment() that rescans accumulated XML fragments on every 1 KiB block read. Attackers can provide malformed XML corpus files to cause severe CPU consumption and denial of service through affected readers like BNCCorpusReader.

SeverityLow

CVSS3.7

Exploit probability—

ProductNltk

PublishedAug 27, 2026

First seenAug 27, 2026

Weakness typeCWE-400Uncontrolled resource consumption

How to fix

Update

nltk3.10.3 or later

Vendor advisories

github.com/nltk/nltk/security/advisories/GHSA-vp2x-qp44-57v7

Affected products

Product	Affected versions	Fixed in
nltkPyPI	v < 3.10.3	3.10.3

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