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CVE PROGRAM SOURCE RECORD8.7 High

CVE-2026-66393

NLTK before 3.9.4 Denial of Service via JSONTaggedDecoder

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Status
Published
Published
Updated
Assigning organization
VulnCheck

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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

nltk nltk

Default version status: unaffected

  • 0 to < 3.9.4affected
  • 3.9.4unaffected
pkg:pypi/nltk

References