CVE-2026-81723

EUVD-2026-67073
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.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
VulnCheckCNA
3.7 LOW
NETWORK
HIGH
NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
Base Score
CVSS 3.x
EPSS Score
Percentile: 18.95%
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
nltknltk
𝑥
< 3.10.3
CNA
Debian logo
Debian Releases
Debian Product
Codename
nltk
bookworm
postponed
forky
3.10.3-1
fixed
sid
3.10.3-1
fixed
trixie
no-dsa
Ubuntu logo
Ubuntu Releases
Ubuntu Product
Codename
nltk
bionic
needs-triage
focal
needs-triage
jammy
needs-triage
noble
needs-triage
resolute
needs-triage
trusty
needs-triage
xenial
needs-triage
Common Weakness Enumeration
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
https://github.com/nltk/nltk/security/advisories/GHSA-vp2x-qp44-57v7