---
cve: "CVE-2025-66512"
severity: "MEDIUM"
cvss: 5.4
epss: "0.3%"
vendor: "nextcloud"
kev: false
exploited: false
published: "2025-12-05 17:16:04"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-23T12:57:35+02:00"
---

# CVE-2025-66512

> 5.4 MEDIUM · 🧪 PoC

## Beschreibung

Nextcloud Server is a self hosted personal cloud system. In Nextcloud Server and Server Enterprise prior to 31.0.12 and 32.0.3, a missing sanitization allowed malicious users to circumvent the content security policy when a malicious user manages to trick a user it viewing an uploaded SVG outside of the Nextcloud Servers web page.

## CVSS-Vektor

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

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

## Patch verfügbar (OSV)

- 6b72bb307e91390c6efe4072b2829bbd1028651c (Commit)
- 0ff293b4efc6b3866ecdbf0d1f643738eea5db3c (Commit)

## Referenzen

- <https://github.com/nextcloud/security-advisories/security/advisories/GHSA-qcw2-p26m-9gc5>
- <https://github.com/nextcloud/viewer/pull/3023>
- <https://github.com/nextcloud/viewer/commit/5044a27d61bc40c0f134298d36af91f865335b63>
- <https://hackerone.com/reports/3357808>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2025-66512) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_