CVE-2021-28799

QNAP NAS Improper Authorization Vulnerability

Severity: critical
CVSS v3: 10
EPSS percentile: 100%
Known exploited: yes (CISA KEV)
Vendor: QNAP
Product: Network Attached Storage (NAS)
Published: 2022-03-31
Modified: 2026-06-17

Description

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 .

NVD record

Informational only. Not a warranty of security, completeness or fitness for any purpose. Derived from NVD, CISA KEV, FIRST.org EPSS and vendor advisories (CVE Program List v5); those sources change continuously and may be incomplete or incorrect. Verify every remediation against the vendor advisory before acting. Absence of a finding is not evidence that no vulnerability exists. Not endorsed by NVD, CISA, FIRST or any vendor named.

Raw record

{
  "id": "CVE-2021-28799",
  "title": "QNAP NAS Improper Authorization Vulnerability",
  "description": "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 .",
  "severity": "critical",
  "cvss": 10,
  "epss": 100,
  "kev": 1,
  "vendor": "QNAP",
  "product": "Network Attached Storage (NAS)",
  "published": "2022-03-31",
  "modified": "2026-06-17T03:46:53.003",
  "source": "nvd",
  "remediation": [],
  "disclaimer": "Informational only. Not a warranty of security, completeness or fitness for any purpose. Derived from NVD, CISA KEV, FIRST.org EPSS and vendor advisories (CVE Program List v5); those sources change continuously and may be incomplete or incorrect. Verify every remediation against the vendor advisory before acting. Absence of a finding is not evidence that no vulnerability exists. Not endorsed by NVD, CISA, FIRST or any vendor named."
}