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CVE PROGRAM SOURCE RECORD6.3 Medium

CVE-2026-81725

NLTK before 3.10.3 Regular Expression Denial of Service via Pl196xCorpusReader

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Status
Published
Published
Updated
Assigning organization
VulnCheck

Description

NLTK before 3.10.3 contains a regular expression denial of service vulnerability in Pl196xCorpusReader that allows attackers to cause quadratic CPU consumption by supplying malformed TEI blocks with many unmatched opening tags. Attackers can exploit lazy regex patterns in the read_block method through public APIs like words() and tagged_words() to force repeated rescans and achieve near-quadratic runtime growth.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

nltk nltk

Default version status: unaffected

  • 0 to < 3.10.3affected
  • 3.10.3unaffected
pkg:pypi/nltk

References