EUVD-2026-67073
GHSA-hqv3-xm29-p9hq
Severity by source
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Network-reachable but requires application to forward attacker-supplied XML corpus files to NLTK (AC:H); severe CPU exhaustion described warrants A:H.
Primary rating from Vendor (VulnCheck).
CVSS VectorVendor: VulnCheck
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Lifecycle Timeline
2DescriptionCVE.org
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.
AnalysisAI
Quadratic CPU exhaustion in NLTK before 3.10.3 allows denial of service via malformed XML corpus files processed by XMLCorpusView._read_xml_fragment(). The method rescans the entire accumulated XML buffer on every 1 KiB block read, creating O(n²) time complexity that scales severely with input size. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires the ability to supply a malformed XML corpus file to an application that passes attacker-controlled input to NLTK's XMLCorpusView or a derived reader such as BNCCorpusReader. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 4.0 vector (AV:N/AC:H/AT:P/PR:N/UI:N/VA:L) yields a score of 6.3. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker with access to a web API or file-upload endpoint that feeds user-provided corpora into an NLTK-based NLP pipeline submits a specially crafted malformed XML file targeting the XMLCorpusView reader. As the application processes the file in 1 KiB blocks, CPU consumption grows quadratically, progressively starving other processes on the host and degrading or halting service availability for legitimate users. … |
| Remediation | Upgrade NLTK to version 3.10.3 or later, which resolves the quadratic rescanning behavior in XMLCorpusView._read_xml_fragment() per the vendor advisory at https://github.com/nltk/nltk/security/advisories/GHSA-vp2x-qp44-57v7. … Detailed patch versions, workarounds, and compensating controls in full report. |
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Same weakness CWE-400 – Uncontrolled Resource Consumption
View allSame technique Denial Of Service
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External POC / Exploit Code
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