GHSA-cv2g-m8rr-888c

Suggest an improvement
Source
https://github.com/advisories/GHSA-cv2g-m8rr-888c
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/08/GHSA-cv2g-m8rr-888c/GHSA-cv2g-m8rr-888c.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-cv2g-m8rr-888c
Downstream
Withdrawn
2026-09-02T15:33:17Z
Published
2026-08-22T15:31:03Z
Modified
2026-09-10T03:51:13Z
Severity
  • 7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
  • 8.7 (High) CVSS_V4 - 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X CVSS Calculator
Summary
Duplicate Advisory: Natural Language Toolkit (NLTK) has unbounded recursion in JSONTaggedDecoder.decode_obj() may cause DoS
Details

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This advisory has been withdrawn because it is a duplicate of GHSA-rf74-v2fm-23pw.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.

Database specific 
{
    "cwe_ids": [
        "CWE-674"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-09-02T15:33:17Z",
    "nvd_published_at": "2026-08-22T15:16:19Z",
    "severity": "HIGH"
}
References

Affected packages

PyPI / nltk

Package

Name
nltk
View open source insights on deps.dev
Purl
pkg:pypi/nltk

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Last Affected
3.9.3

Affected versions

2.*
2.0.1rc2-git
2.0b4
2.0b5
2.0b6
2.0b7
2.0b8
2.0b9
2.0.1rc1
2.0.1rc3
2.0.1rc4
2.0.1
2.0.2
2.0.3
2.0.4
2.0.5
0.*
0.8
0.9
0.9.3
0.9.4
0.9.5
0.9.6
0.9.7
0.9.8
0.9.9
3.*
3.0.0b1
3.0.0b2
3.0.0
3.0.1
3.0.2
3.0.3
3.0.4
3.0.5
3.1
3.2
3.2.1
3.2.2
3.2.3
3.2.4
3.2.5
3.3
3.4
3.4.1
3.4.2
3.4.3
3.4.4
3.4.5
3.5b1
3.5
3.6
3.6.1
3.6.2
3.6.3
3.6.4
3.6.5
3.6.6
3.6.7
3.7
3.8
3.8.1
3.9b1
3.9
3.9.1
3.9.2
3.9.3

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/08/GHSA-cv2g-m8rr-888c/GHSA-cv2g-m8rr-888c.json"