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

A flaw was found in NLTK. This uncontrolled recursion vulnerability in nltk.featstruct.FeatStructReader allows unauthenticated attackers to cause a denial of service. Attackers can achieve this by supplying deeply nested feature-structure input, which can lead to applications crashing when parsin...

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...

UBUNTU-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...

CVE-2026-81724

NLTK before 3.10.3 contains an uncontrolled recursion vulnerability in nltk.featstruct.FeatStructReader . Unauthenticated, remote attackers can supply deeply nested feature-structure input—trivially crafted with nested brackets—that exceeds Python's recursion limit and raises an unhandled Recursi...

CVE-2026-81724 NLTK before 3.10.3 Denial of Service via Uncontrolled Recursion

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...