CVE-2023-22922Network attack vector

Unauthenticated service interruption via Telnet buffer overflow

Published May 1, 2023 · Updated Jan 30, 2025

Buffer overflow in Zyxel NBG-418N v2 firmware 1.00(AARP.13)C0 and earlier allows remote attackers to interrupt service via Telnet packets. Zyxel has not published the affected firmware component or the buffer operation that mishandles the crafted packets. Exploitation requires Telnet to be enabled; no authentication or user interaction is required, and WAN access is disabled by default.

CVSS severity7.5
High
EPSS probability0.93%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in Zyxel NBG-418N v2 firmware 1.00(AARP.13)C0 and earlier allows remote attackers to interrupt service via Telnet packets. Zyxel has not published the affected firmware component or the buffer operation that mishandles the crafted packets. Exploitation requires Telnet to be enabled; no authentication or user interaction is required, and WAN access is disabled by default.

The record

CVE
CVE-2023-22922
Published
May 1, 2023
Updated
Jan 30, 2025
Vendor
Zyxel Networks
Product
NBG-418N v2 firmware
Classifications
CWE-120, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 1, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 30, 2025Record 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=< V1.00(AARP.14)C0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Zyxel Networks · NBG-418N v2 firmwareversion=< V1.00(AARP.14)C0

Published CVSS scores

7.5Zyxel CorporationCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1499Endpoint Denial of Service

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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