CVE-2026-78681

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.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/nltk/nltk/security/advisories/GHSA-97qj-x29f-37w7	Exploit Vendor Advisory
https://www.vulncheck.com/advisories/nltk-before-entity-expansion-dos-via-elementtree	Third Party Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:nltk:nltk:*:*:*:*:*:*:*:*

History

No history.

Information

Published : 2026-08-25 02:16

Updated : 2026-09-01 20:09

NVD link : CVE-2026-78681

Mitre link : CVE-2026-78681

CVE.ORG link : CVE-2026-78681

JSON object : View

Products Affected

nltk

nltk

CWE

CWE-776

Improper Restriction of Recursive Entity References in DTDs ('XML Entity Expansion')

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