CVE-2023-33013Network attack vector

Authenticated OS command execution via crafted NTP request

Published Aug 14, 2023 · Updated Oct 9, 2024

OS command injection in Zyxel NBG6604 firmware V1.01(ABIR.1)C0 allows remote authenticated users to execute commands through the NTP feature. Zyxel has not disclosed which HTTP parameter reaches an OS command interpreter or how the NTP request handler fails to neutralize it. An authenticated management session is required; WAN access is disabled by default, and successful exploitation runs some OS commands on the router.

CVSS severity8.8
High
EPSS probability1.68%
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 NBG6604 firmware V1.01(ABIR.1)C0 allows remote authenticated users to execute commands through the NTP feature. Zyxel has not disclosed which HTTP parameter reaches an OS command interpreter or how the NTP request handler fails to neutralize it. An authenticated management session is required; WAN access is disabled by default, and successful exploitation runs some OS commands on the router.

The record

CVE
CVE-2023-33013
Published
Aug 14, 2023
Updated
Oct 9, 2024
Vendor
Zyxel Networks
Product
NBG6604 firmware
Classifications
CWE-78, T1059
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 14, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 9, 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=v1.01(abIr.1)c0
  2. Affected versionversion=V1.01(ABIR.1)C0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Zyxel Networks · NBG6604 firmwareversion=v1.01(abIr.1)c0; version=V1.01(ABIR.1)C0

Published CVSS scores

8.8Zyxel CorporationCVSS: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 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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