---
cve: "CVE-2021-28799"
severity: "CRITICAL"
cvss: 10.0
epss: "78.3%"
vendor: "QNAP Systems Inc."
kev: true
exploited: true
published: "2021-05-13 03:15:06"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-09-11T03:46:20+02:00"
---

# CVE-2021-28799

> 10.0 CRITICAL · ⚠️ CISA KEV (1625 Tage) · 🔓 Exploited

## Beschreibung

An improper authorization vulnerability has been reported to affect QNAP NAS running HBS 3 (Hybrid Backup Sync. ) If exploited, the vulnerability allows remote attackers to log in to a device. This issue affects: QNAP Systems Inc. HBS 3 versions prior to v16.0.0415 on QTS 4.5.2; versions prior to v3.0.210412 on QTS 4.3.6; versions prior to v3.0.210411 on QTS 4.3.4; versions prior to v3.0.210411 on QTS 4.3.3; versions prior to v16.0.0419 on QuTS hero h4.5.1; versions prior to v16.0.0419 on QuTScloud c4.5.1~c4.5.4. This issue does not affect: QNAP Systems Inc. HBS 2 . QNAP Systems Inc. HBS 1.3 .

## CVSS-Vektor

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

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

## Referenzen

- <https://www.qnap.com/en/security-advisory/QSA-21-13>
- <https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-28799>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2021-28799) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_