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VULNERABILITIES

CVE-2026-81724 Details

Description

NLTK before 3.10.3 contains an uncontrolled recursion vulnerability in nltk.featstruct.FeatStructReader that allows unauthenticated attackers to cause a denial of service by supplying deeply nested feature-structure input. Attackers can craft trivial payloads with nested brackets that exceed Python's recursion limit and raise an unhandled RecursionError, crashing applications that parse user-supplied feature structures or feature grammars.

Metrics

CVSS 3.x Severity and Vector Strings:

CNA: [email protected]CVSS-B:5.3 MEDIUMVector:CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

References to Advisories, Solutions, and Tools

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URLSource(s)Tag(s)
https://github.com/nltk/nltk/security/advisories/GHSA-cw6x-m8jw-qmrh CISA-ADPExploitVendor Advisory
https://github.com/nltk/nltk/security/advisories/GHSA-cw6x-m8jw-qmrh [email protected]ExploitVendor Advisory
https://www.vulncheck.com/advisories/nltk-before-3.10.3-denial-of-service-via-uncontrolled-recursion [email protected]Third Party Advisory

Weakness Enumeration

CWE-IDCWE NameSource
CWE-674Uncontrolled Recursion[email protected]

Affected Products

ProductVersions
nltk nltk
< 3.10.3

CPE

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

Remediation

  • No remediation found in references.

Change History

3 change records found show changes

QUICK INFO

CVE Dictionary Entry:
CVE-2026-81724
NVD Published Date:
Aug 27, 2026
NVD Last Modified:
Aug 31, 2026
Source:
[email protected]
CVE-2026-81724 Details - Not Deferred