GHSA-pf76-q698-37v8

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    GHSA-pf76-q698-37v8

    Published: 27 Aug 2026Last Modified: 10 Sept 2026

    Summary: Duplicate Advisory: Uncontrolled recursion in nltk.featstruct.FeatStructReader causes unhandled RecursionError (DoS) via deeply nested feature-structure input

    Details: ## Duplicate Advisory This advisory has been withdrawn because it is a duplicate of GHSA-cw6x-m8jw-qmrh. This link is maintained to preserve external references. ## Original 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.

    References: https://github.com/nltk/nltk/security/advisories/GHSA-cw6x-m8jw-qmrh, https://nvd.nist.gov/vuln/detail/CVE-2026-81724, https://www.vulncheck.com/advisories/nltk-before-3.10.3-denial-of-service-via-uncontrolled-recursion

    Affected packages

    Package

    Name: nltk

    Purl: pkg:pypi/nltk

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -None

    Affected versions

    0.8

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
    GHSA-pf76-q698-37v8 | CVE-DB