---
cve: "CVE-2026-86258"
severity: "MEDIUM"
cvss: 5.9
epss: "4.2%"
vendor: "Generic Security"
kev: false
exploited: false
published: "2026-09-06 13:17:10"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-06T19:21:41+02:00"
---

# CVE-2026-86258

> 5.9 MEDIUM

## Beschreibung

nbviewer through 1.0.1 contains a path traversal vulnerability in LocalFileHandler.can_show() that uses string-prefix comparison instead of proper path validation. Attackers can read files from sibling directories outside the configured root by requesting paths that share the root as a textual prefix, disclosing unintended notebooks and credentials.

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Hoch | good |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Keine | good |
| A Verfügbarkeit | Keine | good |

## Referenzen

- <https://github.com/jupyter/nbviewer>
- <https://github.com/jupyter/nbviewer/blob/1.0.1/nbviewer/providers/local/handlers.py#L92-L107>
- <https://github.com/jupyter/nbviewer/commit/aad36106f72a1ca7721310c6fccc677ce4c744a5>
- <https://github.com/jupyter/nbviewer/issues/1115>
- <https://www.vulncheck.com/advisories/nbviewer-through-1.0.1-path-traversal-via-localfilehandler>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-86258) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_