CVE-2021-40333Network attack vector

Routing configuration access via weak default credential

Published Dec 2, 2021 · Updated Sep 17, 2024

Weak password requirements in Hitachi Energy FOX61x and XMC20 before R15A allow remote authenticated users to access DCN routing configuration. The appliances expose a weak default credential on TCP port 26 and accept it for access to Data Communication Network routing settings. Network reachability and the default credential are required; successful access permits unauthorized routing-configuration changes.

CVSS severity9.0
Critical
EPSS probability0.63%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Weak password requirements in Hitachi Energy FOX61x and XMC20 before R15A allow remote authenticated users to access DCN routing configuration. The appliances expose a weak default credential on TCP port 26 and accept it for access to Data Communication Network routing settings. Network reachability and the default credential are required; successful access permits unauthorized routing-configuration changes.

The record

CVE
CVE-2021-40333
Published
Dec 2, 2021
Updated
Sep 17, 2024
Vendor
Hitachi Energy
Product
XMC20
Classifications
CWE-521, T0859
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 2, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 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=R15A <R15A

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Hitachi Energy · XMC20version=R15A <R15A
Hitachi Energy · FOX61xversion=R15A <R15A

Published CVSS scores

9.0CISACVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:H/A:H
7.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/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)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-521Weak Password Requirements
T0859Valid Accounts

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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