CVE-2025-51381Network attack vector

LAN authentication bypass

Published Jun 18, 2025 · Updated Jun 18, 2025

Authentication bypass in KAON Broadband KCM3100 Ver1.4.2 and earlier allows remote attackers on the connected LAN to bypass login. JPCERT/CC identifies an alternate path or channel that circumvents authentication, but the affected request, endpoint, and validation error remain undisclosed. The result is unauthorized access to the gateway's authenticated interface; no specific post-bypass action is publicly documented.

CVSS severity9.3
Critical
EPSS probability0.67%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in KAON Broadband KCM3100 Ver1.4.2 and earlier allows remote attackers on the connected LAN to bypass login. JPCERT/CC identifies an alternate path or channel that circumvents authentication, but the affected request, endpoint, and validation error remain undisclosed. The result is unauthorized access to the gateway's authenticated interface; no specific post-bypass action is publicly documented.

The record

CVE
CVE-2025-51381
Published
Jun 18, 2025
Updated
Jun 18, 2025
Vendor
KAON Broadband
Product
KCM3100
Classifications
CWE-288
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 18, 2025CVE publishedPublication date reported by the CVE source.
  2. Jun 18, 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=Ver1.4.2 and earlier

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

KAON Broadband · KCM3100version=Ver1.4.2 and earlier

Published CVSS scores

9.3JPCERT/CCCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
9.8JPCERT/CCCVSS:3.0/AV:N/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-288Authentication Bypass Using an Alternate Path or Channel

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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