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.decode_obj() that allows attackers to cause denial of service by supplying deeply ne…
Published: 2026-08-22 · CVSS: 8.7 · CVSS 4.0
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7