CVE-2021-28799
QNAP · published 2021-05-13
Source record Collected from the National Vulnerability Database (NVD)
CISA Known Exploited Vulnerabilities
CISA lists this CVE as known exploited (added 2022-03-31).
- CISA's name for it: QNAP NAS Improper Authorization Vulnerability
- CISA's description: QNAP NAS running HBS 3 contains an improper authorization vulnerability which can allow remote attackers to log in to a device.
- Known ransomware campaign use, per CISA: Known
Source: CISA KEV catalog (CC0 1.0).
Description
Description by QNAP Systems, Inc. via the CVE Program.
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 .
Status at the source
- NVD status: Analyzed
Affected products, as the source lists them
| Vendor | Product | Versions |
|---|---|---|
| QNAP Systems Inc. | HBS 3 | unspecified – before v16.0.0415: affected |
| QNAP Systems Inc. | HBS 3 | unspecified – before v3.0.210412: affected |
| QNAP Systems Inc. | HBS 3 | unspecified – before v3.0.210411: affected |
| QNAP Systems Inc. | HBS 3 | unspecified – before v3.0.210411: affected |
| QNAP Systems Inc. | HBS 3 | unspecified – before v16.0.0419: affected |
| QNAP Systems Inc. | HBS 3 | unspecified – before v16.0.0419: affected |
| QNAP Systems Inc. | HBS 2 | all versions: unaffected |
| QNAP Systems Inc. | HBS 1.3 | all versions: unaffected |
Products named in NVD's CPE match criteria (1)
cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:*
DeSpy has not checked any unit, hardware revision or firmware. A product missing here is not a statement that it is unaffected.
Scores, as their sources published them
- CVSS 3.1: 10 CRITICAL — as published by QNAP Systems, Inc. (Secondary)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H - CVSS 3.1: 9.8 CRITICAL — as published by NIST (Primary)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0: 7.5 HIGH — as published by NIST (Primary)
AV:N/AC:L/Au:N/C:P/I:P/A:P - SSVC — CISA's assessment (SSVC 2.0.3, CISA Coordinator): Exploitation: active · Automatable: yes · Technical impact: total
DeSpy does not score records. These are the sources' own values.
Weaknesses
CWE-285, NVD-CWE-Other
Sources
References the source lists
- https://www.qnap.com/en/security-advisory/QSA-21-13
- https://www.qnap.com/en/security-advisory/QSA-21-13
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-28799
Source dates: published 2021-05-13, last changed 2026-06-17. DeSpy's copy of this version is dated 2026-09-28.
This product uses the NVD API but is not endorsed or certified by the NVD.
CVE records: Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.
CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy.
CISA's Known Exploited Vulnerabilities catalog and CISA Vulnrichment data are CC0 1.0. CISA advisories are shown with the TLP label their document carries. No endorsement by CISA, DHS, NIST or MITRE is stated or implied.