CVE-2026-81723

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.

CVSS Vector

References

• https://github.com/nltk/nltk/security/advisories/GHSA-vp2x-qp44-57v7
• https://www.vulncheck.com/advisories/nltk-before-3.10.3-quadratic-cpu-exhaustion-via-xmlcorpusview