Description
NLTK versions before 3.10.3 use xml.etree.ElementTree to parse XML in multiple modules, which honors entity declarations in document DTDs. Attackers can craft XML payloads with nested entity declarations that expand from hundreds of bytes to megabytes in memory, causing denial of service.
Published: 2026-08-25
Score: 8.7 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories

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History

Thu, 27 Aug 2026 06:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Tue, 25 Aug 2026 02:00:00 +0000

Type Values Removed Values Added
Description NLTK versions before 3.10.3 use xml.etree.ElementTree to parse XML in multiple modules, which honors entity declarations in document DTDs. Attackers can craft XML payloads with nested entity declarations that expand from hundreds of bytes to megabytes in memory, causing denial of service.
Title NLTK before 3.10.3 Entity Expansion DoS via ElementTree
First Time appeared Nltk
Nltk nltk
Weaknesses CWE-776
CPEs cpe:2.3:a:nltk:nltk:*:*:*:*:*:*:*:*
Vendors & Products Nltk
Nltk nltk
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-08-26T16:12:19.369Z

Reserved: 2026-08-25T01:17:12.263Z

Link: CVE-2026-78681

cve-icon Vulnrichment

Updated: 2026-08-26T15:58:38.755Z

cve-icon NVD

Status : Received

Published: 2026-08-25T02:16:52.750

Modified: 2026-08-26T17:17:15.973

Link: CVE-2026-78681

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-25T04:15:04Z

Weaknesses