CVE-2021-28804Network attack vector

Unauthenticated command execution via undisclosed injection path

Published Jul 1, 2021 · Updated Sep 16, 2024

OS command injection in affected QNAP QTS and QuTS hero releases allows remote attackers to execute arbitrary commands on NAS devices. QNAP has not published the vulnerable component, parameter, or command-construction operation, so the concrete injection path remains undisclosed. Network access without authentication or user interaction is sufficient, and successful exploitation provides command execution in the compromised application.

CVSS severity9.8
Critical
EPSS probability1.82%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

OS command injection in affected QNAP QTS and QuTS hero releases allows remote attackers to execute arbitrary commands on NAS devices. QNAP has not published the vulnerable component, parameter, or command-construction operation, so the concrete injection path remains undisclosed. Network access without authentication or user interaction is sufficient, and successful exploitation provides command execution in the compromised application.

The record

CVE
CVE-2021-28804
Published
Jul 1, 2021
Updated
Sep 16, 2024
Vendor
Linn Products Limited
Product
QuTS hero
Classifications
CWE-78, T1059
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 1, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <h4.5.1.1582 build 20210217

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Linn Products Limited · QuTS heroversion=unspecified <h4.5.1.1582 build 20210217
Linn Products Limited · QTSversion=unspecified <4.5.1.1540 build 20210107

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
T1059Command and Scripting Interpreter

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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