CVE-2021-20711

Unauthenticated command execution from LAN

Published Apr 26, 2021 · Updated Aug 3, 2024

OS command injection in NEC Platforms Aterm WG2600HS firmware 1.5.1 and earlier allows remote attackers on the LAN to execute arbitrary commands. NEC and JVN have not disclosed the affected management-screen URL, parameter, or command-construction operation. Reachability requires LAN-side access to the management screen; the vendor states that WAN-side Internet attacks are not possible.

CVSS severity8.8
High
EPSS probability1.36%
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 NEC Platforms Aterm WG2600HS firmware 1.5.1 and earlier allows remote attackers on the LAN to execute arbitrary commands. NEC and JVN have not disclosed the affected management-screen URL, parameter, or command-construction operation. Reachability requires LAN-side access to the management screen; the vendor states that WAN-side Internet attacks are not possible.

The record

CVE
CVE-2021-20711
Published
Apr 26, 2021
Updated
Aug 3, 2024
Vendor
NEC Platforms, Ltd.
Product
Aterm WG2600HS
Classifications
CWE-78, T1059
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 26, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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=firmware Ver1.5.1 and earlier

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

NEC Platforms, Ltd. · Aterm WG2600HSversion=firmware Ver1.5.1 and earlier

Published CVSS scores

8.3JPCERT/CC JVNAV:A/AC:L/Au:N/C:C/I:C/A:C
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
10.0NIST NVDAV:N/AC:L/Au:N/C:C/I:C/A:C
8.8JPCERT/CC JVNCVSS:3.0/AV:A/AC:L/PR:N/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)
Vectoradjacent
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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