CVE-2026-66393
HIGH
NVD
CVSS Score
7.5
Severity
HIGH
Published
Aug 22, 2026
Vendor
unknown
Description
NLTK versions before 3.9.4 contain an unbounded recursion vulnerability in JSONTaggedDecoder.decode_obj() 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 RecursionError that crashes the Python process.