CVE-2026-66393
8.7
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Summary
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 Software
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| nltk | nltk | 0 < 3.9.4 | affected |
| nltk | nltk | 3.9.4 | unaffected |
Weaknesses
- CWE-674: Uncontrolled Recursion
References
- https://github.com/nltk/nltk/security/advisories/GHSA-rf74-v2fm-23pw
- https://www.vulncheck.com/advisories/nltk-before-denial-of-service-via-jsontaggeddecoder
Feedback
Was this page helpful?
Glad to hear it! Please tell us how we can improve.
Sorry to hear that. Please tell us how we can improve.