GHSA-gx65-c5hj-vpv5

Suggest an improvement
Source
https://github.com/advisories/GHSA-gx65-c5hj-vpv5
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/08/GHSA-gx65-c5hj-vpv5/GHSA-gx65-c5hj-vpv5.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-gx65-c5hj-vpv5
Withdrawn
2026-09-02T14:40:50Z
Published
2026-08-25T03:32:11Z
Modified
2026-09-02T15:00:09Z
Severity
  • 9.6 (Critical) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H CVSS Calculator
  • 9.4 (Critical) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/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: [CWE-502] Unsafe Pickle Deserialization in TransitionParser Allows Remote Code Execution
Details

Duplicate Advisory

This advisory has been withdrawn because it is a duplicate of GHSA-rhp5-r9x4-f5g2. This link is maintained to preserve external references.

Original Description

NLTK before 3.10.0 (affected versions <=3.9.4) contains an unsafe pickle deserialization vulnerability in the TransitionParser.parse() method (nltk/parse/transitionparser.py). The method calls pickle_load() with the default restricted=False, routing deserialization through WarningUnpickler, which does not override find_class() and therefore permits arbitrary class resolution. When an application loads an attacker-crafted model file, embedded pickle gadget chains execute arbitrary Python code with the privileges of the user running the application. NLTK provides a RestrictedUnpickler for safe deserialization, but it is not used by production code paths. Fixed in 3.10.0.

Database specific 
{
    "cwe_ids":  [
        "CWE-502"
    ],
    "github_reviewed":  true,
    "github_reviewed_at":  "2026-09-02T14:40:50Z",
    "nvd_published_at":  "2026-08-25T02:16:53Z",
    "severity":  "CRITICAL"
}
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
3.9.4

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
3.9.4

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/08/GHSA-gx65-c5hj-vpv5/GHSA-gx65-c5hj-vpv5.json"