CVE-2021-28799
Improper Authorization Vulnerability in HBS 3 (Hybrid Backup Sync)
Exploited in the wild. In CISA KEV since 2022‑03‑31. Fixed versions are out.
What to do
Find your product and version, then upgrade to the build on the right.
- QNAP Systems Inc. HBS 3Affected: ≥ unspecified, < v16.0.0415Upgrade to: v16.0.0415Stated by: CVE record
- QNAP Systems Inc. HBS 2Fixed buildsall versionsStated by: CVE record
- QNAP Systems Inc. HBS 1.3Fixed buildsall versionsStated by: CVE record
- Qnap Hybrid Backup SyncAffected: < 16.0.0415Upgrade to: 16.0.0415Stated by: NVD
- QNAP Systems, Inc. HBS 3Affected: до 16.0.0415Upgrade to: not statedStated by: BDU
Versions as the sources state them. Full version matrix after sign-in
Coverage timeline
0 publishersAdded to CISA KEV catalog
Sourced from public security reporting — each date is when it was published, not when it happened.
What it is
From the CVE record
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 .
In plain language
No plain-language summary for this CVE yet.
Exploitation
Where each signal puts this CVE on the scale from published to confirmed exploited.
- CISA KEV
Listed as exploited in the wild since 2022-03-31.
US federal agencies must remediate by 2022-04-21.
Known use in ransomware campaigns.
Apply updates per vendor instructions.
- Public exploits
No public exploit or proof of concept found in the sources we track.
- EPSS
78% chance of exploitation activity in the next 30 days, which ranks it in the 99th percentile of scored CVEs.
Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.
Lifecycle
7 events over 1866 days, from the signal feeds we watch.
- EPSS band changecritical → high
- Nuclei check added
- Patch availablerecord updated
- Added to CISA KEVransomware campaign
- Publishedweakness classified
Affected products
Technical detail
CVSS 3.1 vector
Open in the CVSS calculatorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Scored 10.0 by NVD.
How it is reached
- Attack Vector NetworkExploitable remotely over the network without any special conditions
- Attack Complexity LowNo special conditions — the attack can be reliably reproduced
- Privileges Required NoneNo authentication required — anyone can exploit this
- User Interaction NoneNo user interaction needed — fully automated exploitation
Scope
- Scope ChangedThe exploit can affect other components (e.g. sandbox escape, host compromise from VM)
Impact if exploited
- Confidentiality HighTotal information disclosure — all data in the component is compromised
- Integrity HighTotal loss of integrity — attacker can modify any data in the component
- Availability HighTotal denial of service — the component is completely unavailable
Weaknesses
Sources
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