8.7

GHSA-CV2G-M8RR-888C: nltk PyPI

CVSS: 8.7v4.0HighPublished
Published 22-08-2026Last modified 10-09-2026
Open JSON

Vulnerability summary

GHSA-CV2G-M8RR-888C is a high (CVSS 8.7) vulnerability in nltk PyPI.

Overall risk
35/100
0100
Medium · default modelHow is this calculated?
CVSS score
8.7/10
010
High · v4.0 (OSV · Pypi), selected by version preference
EPSS score
Not scored
0%100%
No EPSS score yet
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 1 · Related 1
CVE-2026-66393CGA-88J4-W33C-HF4F

Timeline

  1. 22-08-2026
    PublishedVulnerability first disclosed.
  2. 10-09-2026
    Last modifiedVulnerability information updated.

Description

Duplicate Advisory: Natural Language Toolkit (NLTK) has unbounded recursion in JSONTaggedDecoder.decode_obj() may cause DoS ## Duplicate Advisory This advisory has been withdrawn because it is a duplicate of GHSA-rf74-v2fm-23pw.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.

CVSS metrics

2 scores · 1 source · 2 versions

EPSS trend

No EPSS score has been published for this record yet.

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

PyPI1 product
  • nltk≤ 3.9.3

1 vendor · 1 product

References

4 links