CVE-2021-47816Public exploitNetwork attack vector

Administrative command execution via user-management parameters

Published Jan 16, 2026 · Updated Jan 16, 2026

Command injection in Thecus N4800Eco NAS Server Control Panel allows remote authenticated users to execute administrative shell commands. The user-deletion and batch-creation endpoints accept username and batch_content values containing $() shell substitution and execute the enclosed text. Valid control-panel credentials and network access to /adm/setmain.php are required; successful exploitation runs commands with administrative privileges and exposes their output in the system log.

CVSS severity5.3
Medium
EPSS probability1.83%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Command injection in Thecus N4800Eco NAS Server Control Panel allows remote authenticated users to execute administrative shell commands. The user-deletion and batch-creation endpoints accept username and batch_content values containing $() shell substitution and execute the enclosed text. Valid control-panel credentials and network access to /adm/setmain.php are required; successful exploitation runs commands with administrative privileges and exposes their output in the system log.

The record

CVE
CVE-2021-47816
Published
Jan 16, 2026
Updated
Jan 16, 2026
Vendor
Thecus
Product
Thecus N4800Eco NAS Server Control Panel
Classifications
CWE-78, T1059.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 16, 2026Record 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=N4800Eco

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Thecus · Thecus N4800Eco NAS Server Control Panelversion=N4800Eco

Published CVSS scores

5.3VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N
8.8VulnCheckCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
T1059.004Command and Scripting Interpreter: Unix Shell

Public exploit references

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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