CVE-2021-28799
Is CVE-2021-28799 real, exploitable, or a false positive? Here's the community verdict.
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signals
public sources
Confirmed exploited in the wild. Patch this first, regardless of the base score.
cisa ssvc
CISA Vulnrichment · assessed
CISA decision, by how critical the affected system is to you:
- low impact → Attend
- medium impact → Act
- high impact → Act
Track: normal patch cycle · Track*: watch closely · Attend: patch sooner · Act: patch now. About SSVC ↗
baseline read
auto · not a community verdict
Real — exploited in the wild
CISA confirms active exploitation. Treat scanner hits as true positives unless your specific version or config is unaffected.
Based on CISA KEV
Confirm or dispute →CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
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 .
References
Published · Added to CISA KEV (322 days after publication)
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timeline
- CISA SSVC assessment · exploitation: active
- Added to CISA KEV · confirmed exploited in the wild
- Published by NVD
- Added to VulnCheck KEV · reported exploited in the wild
Score and exploit changes tracked since .
Community ground truth
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In your experience, is this finding real and exploitable?
awaiting field verdictsCurated baseline: TruePositive's read from public sources is Real & exploitable — a starting point, not a community verdict.
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Field notes & remediation
Verdicts are the quick signal. Notes are the evidence and fixes behind them.
- 0
QNAP NAS Improper Authorization Vulnerability — QNAP NAS running HBS 3 contains an improper authorization vulnerability which can allow remote attackers to log in to a device. Listed in the CISA KEV catalog (added 2022-03-31) — confirmed exploited in the wild, not theoretical. It is linked to known ransomware campaigns. FIRST EPSS puts the chance of exploitation in the next 30 days at ~78%. Treat it as real and prioritize remediation over triage.
- 0
Required action for QNAP Network Attached Storage (NAS): Apply updates per vendor instructions. CISA set a federal remediation due date of 2022-04-21. After patching, verify the vulnerable path is no longer reachable before closing the finding.
Add a field note or remediationoptional
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