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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

Exploited in wild
Yes
CISA KEV
Public exploit
None known
Metasploit/EDB/PoC
Base severity
10 Critical
CVSS
Exploitation prob.
78%
FIRST EPSS
Weakness
CWE-285
CWE

Confirmed exploited in the wild. Patch this first, regardless of the base score.

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 →
Affected:Qnap

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

NVD MITRE CVE.org CISA KEV

Published

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In your experience, is this finding real and exploitable?

awaiting field verdicts
Real, but not a risk here
Not a real issue

Curated 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
    Field note · TruePositive EditorialCurated

    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
    Remediation · TruePositive EditorialCurated

    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.

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Related CVEs

Same weakness: CWE-285.