GHSA-CW6X-M8JW-QMRH NLTK: Uncontrolled recursion in nltk.featstruct.FeatStructReader causes unhandled RecursionError (DoS) via deeply nested feature-structure input

Summary nltk.featstruct.FeatStructReader used by FeatStructstr and by FeatureGrammar.fromstring parses feature-structure strings such as a=1 with a recursive-descent parser that has no nesting-depth limit. A small, trivially-crafted input 700 bytes with deeply nested brackets drives the parser pa...

CVE-2026-81724

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...