CVE-2026-66393

A flaw was found in NLTK. A remote attacker can exploit an unbounded recursion vulnerability in the JSONTaggedDecoder.decodeobj function by supplying deeply nested JSON structures. This can cause the Python process to crash, leading to a denial of service. Mitigation To mitigate this vulnerabilit...

GHSA-CV2G-M8RR-888C Duplicate Advisory: Natural Language Toolkit (NLTK) has unbounded recursion in JSONTaggedDecoder.decode_obj() may cause DoS

Duplicate Advisory This advisory has been withdrawn because it is a duplicate of GHSA-rf74-v2fm-23pw. This link is maintained to preserve external references. Original Description NLTK versions before 3.9.4 contain an unbounded recursion vulnerability in JSONTaggedDecoder.decodeobj that allows...

CVE-2026-66393

NLTK versions before 3.9.4 contain an unbounded recursion vulnerability in JSONTaggedDecoder.decodeobj that allows attackers to cause denial of service by supplying deeply nested JSON structures. Attackers can craft JSON payloads exceeding the recursion limit to trigger an unhandled RecursionErro...

CVE-2026-66393 NLTK before 3.9.4 Denial of Service via JSONTaggedDecoder

NLTK versions before 3.9.4 contain an unbounded recursion vulnerability in JSONTaggedDecoder.decodeobj that allows attackers to cause denial of service by supplying deeply nested JSON structures. Attackers can craft JSON payloads exceeding the recursion limit to trigger an unhandled RecursionErro...

CVE-2026-66393 NLTK before 3.9.4 Denial of Service via JSONTaggedDecoder

NLTK versions before 3.9.4 contain an unbounded recursion vulnerability in JSONTaggedDecoder.decodeobj that allows attackers to cause denial of service by supplying deeply nested JSON structures. Attackers can craft JSON payloads exceeding the recursion limit to trigger an unhandled RecursionErro...

EUVD-2026-64310

NLTK versions before 3.9.4 contain an unbounded recursion vulnerability in JSONTaggedDecoder.decodeobj that allows attackers to cause denial of service by supplying deeply nested JSON structures. Attackers can craft JSON payloads exceeding the recursion limit to trigger an unhandled RecursionErro...

CVE-2026-66393

NLTK versions before 3.9.4 are affected by an unbounded recursion vulnerability in JSONTaggedDecoder.decode_obj() . An attacker can supply a deeply nested JSON structure that exceeds Python's recursion limit, triggering an unhandled RecursionError that crashes the process, resulting in denial of ...

PT-2026-79565

Name of the Vulnerable Software and Affected Versions NLTK versions prior to 3.9.4 Description An unbounded recursion issue exists in the decode obj function of the JSONTaggedDecoder. An attacker can cause a denial of service by providing deeply nested JSON structures. By crafting JSON payloads...