CVE-2021-28799

CRITICAL KEV RANSOMWARE NUCLEI

QNAP HBS 3 - Broken Access Control

Title source: nuclei

Exploitation Summary

CVE-2021-28799 is actively exploited and listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added March 31, 2022, with confirmed use in ransomware campaigns. A Nuclei detection template is also available.

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 .

Nuclei Templates (1)

QNAP HBS 3 - Broken Access Control

CRITICALVERIFIEDby daffainfo

Shodan: product:"QNAP"

References (2)

Core 2

Core References

Vendor Advisory x_refsource_misc

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

US Government Resource

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-28799

Scores

CVSS v3 10.0

EPSS 0.9237

EPSS Percentile 99.7%

Attack Vector NETWORK

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

CISA SSVC

Vulnrichment

Exploitation active

Automatable yes

Technical Impact total

Details

CISA KEV 2022-03-31

VulnCheck KEV 2021-04-29

InTheWild.io 2021-05-21

ENISA EUVD EUVD-2021-15455

Ransomware Use Confirmed

CWE

CWE-285

Status published

Products (1)

qnap/hybrid_backup_sync < 16.0.0415

Published May 13, 2021

KEV Added Mar 31, 2022

Tracked Since Feb 18, 2026