---
cve: "CVE-2026-79657"
severity: "CRITICAL"
cvss: 9.3
epss: "1.3%"
vendor: "nltk"
kev: false
exploited: false
published: "2026-08-25 12:16:28"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-11-03T21:38:59+01:00"
---

# CVE-2026-79657

> 9.3 CRITICAL · 🧪 PoC

## Beschreibung

NLTK versions before 3.10.3 contain a remote code execution vulnerability in allowlisted pickle loaders that trust entire module namespaces instead of specific safe callables. Attackers can craft malicious pickle payloads invoking dangerous in-namespace functions like ReppTokenizer._execute and numpy.f2py.crackfortran.myeval through pickle REDUCE to execute arbitrary commands during model or tokenizer artifact loading.

## CNA-Record (Kanon, cvelistV5)

- CNA: **VulnCheck**
- State: PUBLISHED
- Stand: 2026-10-08 15:25:11
- CNA-CVSS: **9.3** (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)

## CISA-Anreicherung (vulnrichment/ADP)

- CISA-SSVC (Coordinator, v2.0.3):
  - Exploitation: **poc**
  - Automatable: **yes**
  - Technical Impact: **total**

## CVSS-Vektor

```
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |

## Schwachstellen-Klasse

- **CWE-502** — Deserialization of Untrusted Data
  The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.

## Angriffsmuster (CAPEC)

- [CAPEC-586 — Object Injection](https://capec.mitre.org/data/definitions/586.html) _(Severity: High)_

## Patch verfügbar (OSV)

- 303f6e2ba8e4548a5f54fd65d86bb5c9a949f1db

## Referenzen

- <https://github.com/nltk/nltk/security/advisories/GHSA-x99w-6fgc-pmfw>
- <https://www.vulncheck.com/advisories/nltk-before-3.10.3-remote-code-execution-via-unsafe-pickle-deserialization>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/sicherheitsluecken/cve-2026-79657/) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_