Improper Access Control in nltk/nltk (nltk nltk/nltk)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.21 % · percentile 11 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- @huntr_ai
- NVD status
- Analyzed
Description
A vulnerability in `nltk.downloader` in nltk/nltk versions <= 3.9.4 allows for cross-package resource and model poisoning. The downloader extracts package archives into shared namespaces such as `corpora/` and `taggers/` instead of package-isolated roots, and validates package integrity only after the archive has been written and extracted. This design flaw enables one package to overwrite another package's trusted resources within the same namespace, making the changes immediately active through ordinary NLTK APIs. This issue persists across fresh interpreter restarts and can affect downstream workflows, including machine learning pipelines and reproducibility-sensitive environments.
Weaknesses (CWE)
- CWE-284 — Improper Access Control
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.0 | MEDIUM 5.3 | CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N | @huntr_ai |
| CVSS 3.1 | MEDIUM 6.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N | NVD · nvd@nist.gov (Primary) |
| CVSS 3.0 | MEDIUM 5.3 | CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N | NVD · security@huntr.dev (Secondary) |
Advisories
- GHSA-ffj6-66c4-86gw — NLTK downloader allows cross-package resource and model poisoning
- PYSEC-2026-3954 — A vulnerability in `nltk.downloader` in nltk/nltk versions <= 3.9.4 allows for cross-package resource and model poisoning. The downloader extracts package archi
European references
- ENISA EUVD · EUVD-2026-54393
- GCVE · GCVE-0-2026-12261
Affected configurations (NVD CPE)
cpe:2.3:a:nltk:nltk:*:*:*:*:*:*:*:*≤ 3.9.4
Affected products
| Product | Versions |
|---|---|
| nltk · nltk/nltk | affected unspecified ≤ latest |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |