VULNERABILITY INTELLIGENCE

CVE-2026-81725

CVSS score3.7 LOW
EPSS probability0.37%
CISA KEVNot currently listed
Published2026-08-27
Last modified2026-09-01
CVSS vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

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.

Weakness classification

  • disclosure@vulncheck.com: CWE-400

Primary references