CVE-2026-81723

medium

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.

References

https://www.vulncheck.com/advisories/nltk-before-3.10.3-quadratic-cpu-exhaustion-via-xmlcorpusview

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

Details

Source: Mitre, NVD

Published: 2026-08-27

Updated: 2026-08-27

Risk Information

CVSS v2

Base Score: 2.6

Vector: CVSS2#AV:N/AC:H/Au:N/C:N/I:N/A:P

Severity: Low

CVSS v3

Base Score: 3.7

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

Severity: Low

CVSS v4

Base Score: 6.3

Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

Severity: Medium

EPSS

EPSS: 0.00222