A AegiFlow
MEDIUMCVSS 6.9

GHSA-pf76-q698-37v8

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

Published
2026-08-27
Modified
2026-09-02
Sources
github-advisory

Summary

## Duplicate Advisory This advisory has been withdrawn because it is a duplicate of GHSA-cw6x-m8jw-qmrh.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.

Affected packages

EcosystemPackageAffected versionsFixed versions
PyPInltk

Remediation: No patched version is listed by GitHub.

References

Includes data from the GitHub Advisory Database, licensed under CC-BY 4.0.