CVE-2024-21865

Adjacent unauthenticated shell access via weak SSH credentials

Published Mar 25, 2024 · Updated Sep 19, 2025

Use of weak credentials in KDDI HGW-BL1500HM Ver 002.001.013 and earlier allows remote attackers on the adjacent network to obtain an SSH shell. The SSH service accepts a weak credential, but published materials do not identify the account, credential value, or credential-generation flaw. Access requires reachability to the gateway from an adjacent network and grants an interactive shell capable of changing system state.

CVSS severity6.5
Medium
EPSS probability0.36%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use of weak credentials in KDDI HGW-BL1500HM Ver 002.001.013 and earlier allows remote attackers on the adjacent network to obtain an SSH shell. The SSH service accepts a weak credential, but published materials do not identify the account, credential value, or credential-generation flaw. Access requires reachability to the gateway from an adjacent network and grants an interactive shell capable of changing system state.

The record

CVE
CVE-2024-21865
Published
Mar 25, 2024
Updated
Sep 19, 2025
Vendor
KDDI Corporation
Product
HGW-BL1500HM
Classifications
CWE-1391, T1021.004
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 25, 2024CVE publishedPublication date reported by the CVE source.
  2. Sep 19, 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=Ver 002.001.013 and earlier

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

KDDI Corporation · HGW-BL1500HMversion=Ver 002.001.013 and earlier

Published CVSS scores

6.5CISA-ADPCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
6.5JPCERT/CCCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

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-1391Use of Weak Credentials
T1021.004Remote Services: SSH

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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