What is GHSA-cv2g-m8rr-888c?

GHSA-cv2g-m8rr-888c is a security advisory published by GitHub Security Advisories with High severity. Duplicate Advisory: Natural Language Toolkit (NLTK) has unbounded recursion in JSONTaggedDecoder.decode_obj() may cause DoS

Why does GHSA-cv2g-m8rr-888c have no CVE ID yet?

GitHub Security Advisories published this advisory directly to customers before NVD assigned a CVE ID. This is the embargo-window disclosure pattern — vendors notify customers on day 0; NVD's public record follows days to weeks later.

What is the CVSS v3 score of GHSA-cv2g-m8rr-888c?

GHSA-cv2g-m8rr-888c has a CVSS v3 base score of 7.5, published by GitHub Security Advisories.

Which products are affected by GHSA-cv2g-m8rr-888c?

GHSA-cv2g-m8rr-888c affects 1 product, including: pip/nltk:\u003c= 3.9.3.

⚠ Withdrawn by GitHub Security Advisories

Withdrawn: September 2, 2026

GHSA-cv2g-m8rr-888cHighCVSS 7.5Disclosed before NVD

Duplicate Advisory: Natural Language Toolkit (NLTK) has unbounded recursion in JSONTaggedDecoder.decode_obj() may cause DoS

Vendor

GitHub Security Advisories

Published

August 22, 2026

Last Modified

September 2, 2026

📋 Description

Duplicate Advisory

This advisory has been withdrawn because it is a duplicate of GHSA-rf74-v2fm-23pw. This link is maintained to preserve external references.

Original 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 products1

pip/nltk:<= 3.9.3

🔗 References (4)

https://github.com/nltk/nltk/security/advisories/GHSA-rf74-v2fm-23pw
https://nvd.nist.gov/vuln/detail/CVE-2026-66393
https://www.vulncheck.com/advisories/nltk-before-denial-of-service-via-jsontaggeddecoder
https://github.com/advisories/GHSA-cv2g-m8rr-888c