CVE-2023-6398Network attack vector

Administrator command execution via FTP file upload

Published Feb 20, 2024 · Updated Aug 25, 2024

OS command injection in Zyxel firewall and AP firmware allows remote authenticated users with administrator privileges to execute commands via FTP. The file-upload binary processes an FTP upload and reaches OS command execution, but Zyxel has not disclosed the vulnerable file, function, parameter, or unsafe operation. Administrator credentials and network access to FTP are required; successful exploitation executes commands with the device service privileges.

CVSS severity7.2
High
EPSS probability1.33%
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 Zyxel firewall and AP firmware allows remote authenticated users with administrator privileges to execute commands via FTP. The file-upload binary processes an FTP upload and reaches OS command execution, but Zyxel has not disclosed the vulnerable file, function, parameter, or unsafe operation. Administrator credentials and network access to FTP are required; successful exploitation executes commands with the device service privileges.

The record

CVE
CVE-2023-6398
Published
Feb 20, 2024
Updated
Aug 25, 2024
Vendor
Zyxel Networks
Product
WBE660S Firmware
Classifications
CWE-78, T1059
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Feb 20, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 25, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=0 <6.70\(acgg.1\)
  2. Affected versionversion=< 6.70(ACGG.1)

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Zyxel Networks · WBE660S Firmwareversion=0 <6.70\(acgg.1\); version=< 6.70(ACGG.1)
Zyxel Networks · WAX300H Firmwareversion=0 <6.70\(achf.1\); version=< 6.70(ACHF.1)
Zyxel Networks · WAC500 Firmwareversion=0 <6.70\(abvs.1\); version=< 6.70(ABVS.1)
Zyxel Networks · USG20W-VPN Firmwareversion=4.16 <=5.37_patch1
Zyxel Networks · Zyxel ATP Series Firmwareversion=version 4.32 through 5.37 Patch 1
Zyxel Networks · NWA50AX Firmwareversion=0 <6.29\(abyw.4\); version=< 6.29(ABYW.4)
Zyxel Networks · ZyWALL ATP800 Firmwareversion=4.32 <=5.37_patch1
Zyxel Networks · USG FLEX H Series uOS Firmwareversion=version 1.10 through 1.10 Patch 1
Zyxel Networks · Zyxel USG FLEX Series Firmwareversion=version 4.50 through 5.37 Patch 1
Zyxel Networks · USG FLEX 700 Firmwareversion=4.50 <5.37_patch1
Zyxel Networks · USG FLEX 50/50W Seriesversion=version 4.16 through 5.37 Patch 1

Published CVSS scores

7.2Zyxel CorporationCVSS:3.1/AV:N/AC:L/PR:H/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
Privilegesadmin
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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