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URL: https://nvd.nist.gov/vuln/detail/CVE-2021-28799

⇱ NVD - CVE-2021-28799

  1. Vulnerabilities

CVE-2021-28799 Detail

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 .


Metrics

 
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CVSS 4.0 Severity and Vector Strings:

NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-28799 CISA-ADP US Government Resource 
https://www.qnap.com/en/security-advisory/QSA-21-13 CVE, Inc., QNAP Systems Vendor Advisory 

This CVE is in CISA's Known Exploited Vulnerabilities Catalog

Reference CISA's BOD 22-01 and Known Exploited Vulnerabilities Catalog for further guidance and requirements.

Vulnerability Name Date Added Due Date Required Action
QNAP NAS Improper Authorization Vulnerability 03/31/2022 04/21/2022 Apply updates per vendor instructions.

Weakness Enumeration

CWE-ID CWE Name Source
NVD-CWE-Other Other 👁 cwe source acceptance level
NIST  
CWE-285 Improper Authorization QNAP Systems, Inc.  

Known Affected Software Configurations Switch to CPE 2.2

CPEs loading, please wait.

Denotes Vulnerable Software
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Change History

13 change records found show changes

CVE Modified by CISA-ADP 6/16/2026 11:46:53 PM

Action Type Old Value New Value
Added SSVC 
{"timestamp":"2025-02-04T14:53:29.275519Z","id":"CVE-2021-28799","options":[{"exploitation":"active"},{"automatable":"yes"},{"technicalImpact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}

CVE Modified by QNAP Systems, Inc. 6/16/2026 11:46:53 PM

Action Type Old Value New Value
Added Affected 
[{"vendor":"QNAP Systems Inc.","product":"HBS 3","platforms":["QTS 4.5.2"],"versions":[{"version":"unspecified","lessThan":"v16.0.0415","versionType":"custom","status":"affected"}]},{"vendor":"QNAP Systems Inc.","product":"HBS 3","platforms":["QTS 4.3.6"],"versions":[{"version":"unspecified","lessThan":"v3.0.210412","versionType":"custom","status":"affected"}]},{"vendor":"QNAP Systems Inc.","product":"HBS 3","platforms":["QTS 4.3.4"],"versions":[{"version":"unspecified","lessThan":"v3.0.210411","versionType":"custom","status":"affected"}]},{"vendor":"QNAP Systems Inc.","product":"HBS 3","platforms":["QTS 4.3.3"],"versions":[{"version":"unspecified","lessThan":"v3.0.210411","versionType":"custom","status":"affected"}]},{"vendor":"QNAP Systems Inc.","product":"HBS 3","platforms":["QuTS hero h4.5.1"],"versions":[{"version":"unspecified","lessThan":"v16.0.0419","versionType":"custom","status":"affected"}]},{"vendor":"QNAP Systems Inc.","product":"HBS 3","platforms":["QuTScloud c4.5.1~c4.5.4"],"versions":[{"version":"unspecified","lessThan":"v16.0.0419","versionType":"custom","status":"affected"}]},{"vendor":"QNAP Systems Inc.","product":"HBS 2","versions":[{"version":"all versions","status":"unaffected"}]},{"vendor":"QNAP Systems Inc.","product":"HBS 1.3","versions":[{"version":"all versions","status":"unaffected"}]}]

Modified Analysis by NIST 11/03/2025 10:07:48 AM

Action Type Old Value New Value
Changed CPE Configuration 
AND
 OR
 *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions up to (excluding) 16.0.0415
 OR
 cpe:2.3:a:qnap:qts:4.5.2:*:*:*:*:*:*:*


 
AND
 OR
 *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions up to (excluding) 16.0.0415
 OR
 cpe:2.3:o:qnap:qts:4.5.2:*:*:*:*:*:*:*
Changed CPE Configuration 
AND
 OR
 *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions up to (excluding) 3.0.210411
 OR
 cpe:2.3:a:qnap:qts:4.3.4:*:*:*:*:*:*:*
 cpe:2.3:a:qnap:qts:4.3.3:*:*:*:*:*:*:*


 
AND
 OR
 *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions up to (excluding) 3.0.210411
 OR
 cpe:2.3:o:qnap:qts:4.3.3:*:*:*:*:*:*:*
 cpe:2.3:o:qnap:qts:4.3.4:*:*:*:*:*:*:*
Added Reference Type 
CISA-ADP: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-28799 Types: US Government Resource

CVE Modified by CISA-ADP 10/21/2025 8:17:30 PM

Action Type Old Value New Value
Added Reference 
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-28799

CVE Modified by CISA-ADP 10/21/2025 4:18:28 PM

Action Type Old Value New Value
Removed Reference 
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-28799

CVE Modified by CISA-ADP 10/21/2025 3:19:00 PM

Action Type Old Value New Value
Added Reference 
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-28799

Modified Analysis by NIST 3/12/2025 4:57:59 PM

Action Type Old Value New Value
Changed CPE Configuration 
AND
 OR
 *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions from (excluding) 16.0.0415
 OR
 cpe:2.3:a:qnap:qts:4.5.2:*:*:*:*:*:*:*


 
AND
 OR
 *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions from (excluding) 16.0.0415
 OR
 cpe:2.3:a:qnap:qts:4.5.2:*:*:*:*:*:*:*
Changed CPE Configuration 
AND
 OR
 *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions from (excluding) 16.0.0415
 OR
 cpe:2.3:a:qnap:qts:4.5.2:*:*:*:*:*:*:*


 
AND
 OR
 *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions from (excluding) 16.0.0415
 OR
 cpe:2.3:a:qnap:qts:4.5.2:*:*:*:*:*:*:*
Changed CPE Configuration 
AND
 OR
 *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions from (excluding) 3.0.210411
 OR
 cpe:2.3:a:qnap:qts:4.3.4:*:*:*:*:*:*:*
 cpe:2.3:a:qnap:qts:4.3.3:*:*:*:*:*:*:*


 
AND
 OR
 *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions from (excluding) 3.0.210411
 OR
 cpe:2.3:a:qnap:qts:4.3.4:*:*:*:*:*:*:*
 cpe:2.3:a:qnap:qts:4.3.3:*:*:*:*:*:*:*
Changed CPE Configuration 
AND
 OR
 *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions from (excluding) 3.0.210411
 OR
 cpe:2.3:a:qnap:qts:4.3.4:*:*:*:*:*:*:*
 cpe:2.3:a:qnap:qts:4.3.3:*:*:*:*:*:*:*


 
AND
 OR
 *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions from (excluding) 3.0.210411
 OR
 cpe:2.3:a:qnap:qts:4.3.4:*:*:*:*:*:*:*
 cpe:2.3:a:qnap:qts:4.3.3:*:*:*:*:*:*:*
Changed CPE Configuration 
AND
 OR
 *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions from (excluding) 3.0.210412
 OR
 cpe:2.3:o:qnap:qts:4.3.6:*:*:*:*:*:*:*


 
AND
 OR
 *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions from (excluding) 3.0.210412
 OR
 cpe:2.3:o:qnap:qts:4.3.6:*:*:*:*:*:*:*
Changed CPE Configuration 
AND
 OR
 *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions from (excluding) 3.0.210412
 OR
 cpe:2.3:o:qnap:qts:4.3.6:*:*:*:*:*:*:*


 
AND
 OR
 *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions from (excluding) 3.0.210412
 OR
 cpe:2.3:o:qnap:qts:4.3.6:*:*:*:*:*:*:*

CVE Modified by CVE 11/21/2024 1:00:13 AM

Action Type Old Value New Value
Added Reference 
https://www.qnap.com/en/security-advisory/QSA-21-13

CVE Modified by QNAP Systems, Inc. 5/14/2024 4:44:07 AM

Action Type Old Value New Value

CPE Deprecation Remap by NIST 11/14/2023 2:26:49 PM

Action Type Old Value New Value
Changed CPE Configuration 
OR
 *cpe:2.3:a:qnap:qts:4.3.6:*:*:*:*:*:*:*


 
OR
 *cpe:2.3:o:qnap:qts:4.3.6:*:*:*:*:*:*:*

Reanalysis by NIST 7/14/2022 11:42:37 AM

Action Type Old Value New Value
Added CWE 
NIST NVD-CWE-Other
Removed CWE 
NIST CWE-863

CPE Deprecation Remap by NIST 6/21/2021 12:57:36 PM

Action Type Old Value New Value
Changed CPE Configuration 
OR
 *cpe:2.3:a:qnap:quts_hero:h4.5.1:*:*:*:*:*:*:*


 
OR
 *cpe:2.3:o:qnap:quts_hero:h4.5.1:*:*:*:*:*:*:*

Initial Analysis by NIST 6/01/2021 4:05:48 PM

Action Type Old Value New Value
Added CVSS V3.1 
NIST AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Added CVSS V2 
NIST (AV:N/AC:L/Au:N/C:P/I:P/A:P)
Added CWE 
NIST CWE-863
Added CPE Configuration 
AND
 OR
 *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions up to (excluding) 16.0.0415
 OR
 cpe:2.3:a:qnap:qts:4.5.2:*:*:*:*:*:*:*
Added CPE Configuration 
AND
 OR
 *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions up to (excluding) 16.0.0419
 OR
 cpe:2.3:a:qnap:quts_hero:h4.5.1:*:*:*:*:*:*:*
Added CPE Configuration 
AND
 OR
 *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions up to (excluding) 16.0.0419
 OR
 cpe:2.3:o:qnap:qutscloud:*:*:*:*:*:*:*:* versions from (including) c4.5.1 up to (including) c4.5.4
Added CPE Configuration 
AND
 OR
 *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions up to (excluding) 3.0.210411
 OR
 cpe:2.3:a:qnap:qts:4.3.3:*:*:*:*:*:*:*
 cpe:2.3:a:qnap:qts:4.3.4:*:*:*:*:*:*:*
Added CPE Configuration 
AND
 OR
 *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions up to (excluding) 3.0.210412
 OR
 cpe:2.3:a:qnap:qts:4.3.6:*:*:*:*:*:*:*
Changed Reference Type 
https://www.qnap.com/en/security-advisory/QSA-21-13 No Types Assigned


 
https://www.qnap.com/en/security-advisory/QSA-21-13 Vendor Advisory

Quick Info

CVE Dictionary Entry:
CVE-2021-28799
NVD Published Date:
05/12/2021
NVD Last Modified:
06/16/2026
Source:
QNAP Systems, Inc.