CVE detail

CVE-2021-28809 — CVE-2021-28809

Published 2021-07-08 · Modified 2026-06-17 · Vendor qnap · Product hybrid_backup_sync · Source nvd

CRITICAL

severity

CVSS-derived band

9.8

CVSS v3

0–10 scale

0.1580

EPSS probability

exploitation probability, 30d

97.0%

EPSS percentile

percentile vs all CVEs

NOT LISTED

CISA KEV

known exploited catalog

Description

An improper access control vulnerability has been reported to affect certain legacy versions of HBS 3. If exploited, this vulnerability allows attackers to compromise the security of the operating system.QNAP have already fixed this vulnerability in the following versions of HBS 3: QTS 4.3.6: HBS 3 v3.0.210507 and later QTS 4.3.4: HBS 3 v3.0.210506 and later QTS 4.3.3: HBS 3 v3.0.210506 and later

Remediation

No vendor-published fix data in our corpus for this CVE. Check the references below or the vendor's PSIRT / security advisories page.

References

cvedb.io · NVD · CISA KEV · FIRST EPSS · vendor advisories (CVE Program List v5). Informational only, no warranty — verify every remediation against the vendor advisory before acting on it. This product uses data from the NVD API but is not endorsed or certified by the NVD, CISA, FIRST.org or any vendor named. CVE® is a registered trademark of The MITRE Corporation.