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High · 8.7 CVE-2026-126297 EUVD-2026-125224GHSA-qvhx-rvgc-jhwfGHSA-v8f3-6phw-6mh9

NLTK: Quadratic-time CPU denial of service in ConllCorpusReader SRL instance builder via nested span rescan

Published Nov 13, 2026 · Assigned by VulnCheck

Description

NLTK before 3.10.4 contains a quadratic-time denial of service vulnerability in ConllCorpusReader._get_srl_instances that allows remote attackers to exhaust CPU through nested span rescans. Attackers can supply a crafted CoNLL SRL corpus with many predicates and span columns, placing the head span last, to pin a core for minutes.

Affected products

VendorProductAffectedFixed
nltk nltk 0 <3.10.4 —

Affected packages

EcosystemPackageAffectedFixedRecord
PyPI nltk < 3.10.4 3.10.4 GHSA-v8f3-6phw-6mh9

References