CVE-2026-66393High· 7.5▾ TwilightNLTK 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 exce…
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 41.3 · likelihood 0.1 · exploitation 0
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Exploit-prediction probability, daily snapshots since Aug 23.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via NVD
0.5%
0.5% → 0.5%
Last analysed / modified upstream
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.
nltk < 3.9.4Upgrade past the affected range:
nltk 3.9.4Affected packages:
nltk < 3.9.4Patched in:
nltk 3.9.4Source: https://osv.dev/vulnerability/GHSA-rf74-v2fm-23pw
Connected by shared product, vendor, weakness, or advisory.
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