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.

Attack Vector Network

Attack Complexity High

Privileges Required None

Attack Requirements Present

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact Low

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity High

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact Low

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
nltk nltk unaffected
Version Status Constraints
0 affected < 3.10.3
3.10.3 unaffected —

No data.

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Project Subscriptions

Vendors Products
Nltk Subscribe
Nltk Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/nltk/nltk/security/advisories/GHSA-vp2x-qp44-57v7 cve-icon cve-icon
https://www.vulncheck.com/advisories/nltk-before-3.10.3-quadratic-cpu-exhaustion-via-xmlcorpusview cve-icon cve-icon
History

Thu, 27 Aug 2026 16:45:00 +0000

Type Values Removed Values Added
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.
Title NLTK before 3.10.3 Quadratic CPU Exhaustion via XMLCorpusView
First Time appeared Nltk
Nltk nltk
Weaknesses CWE-400
CPEs cpe:2.3:a:nltk:nltk:*:*:*:*:*:*:*:*
Vendors & Products Nltk
Nltk nltk
References
Metrics cvssV3_1

{'score': 3.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L'}

cvssV4_0

{'score': 6.3, 'vector': 'CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-08-27T14:51:16.614Z

Reserved: 2026-08-27T11:13:14.064Z

Link: CVE-2026-81723

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-27T17:21:02.957

Modified: 2026-08-27T17:21:02.957

Link: CVE-2026-81723

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses