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Fox615 FirmwareOperating system · Hitachienergy

CVE-2021-40334

HIGH · 7.5 CVSS v3.1 Published 2021-12-02
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Missing Handler vulnerability in the proprietary management protocol (port TCP 5558) of Hitachi Energy FOX61x, XCM20 allows an attacker that exploits the vulnerability by activating SSH on port TCP 5558 to cause disruption to the NMS and NE communication. This issue affects: Hitachi Energy FOX61x versions prior to R15A. Hitachi Energy XCM20 versions prior to R15A.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

A Missing Handler vulnerability exists in the proprietary management protocol on TCP port 5558 in Hitachi Energy FOX61x and XCM20 devices. An attacker can exploit this by activating SSH on port 5558, which causes disruption to Network Management System (NMS) and Network Element (NE) communication. The vulnerability stems from a missing or incomplete handler for certain protocol states or inputs.

MitigationUpdate Hitachi Energy FOX61x and XCM20 firmware to version R15A or later. If immediate patching is not feasible, consider restricting access to TCP port 5558 through network segmentation or firewall rules to reduce attack surface.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Fox615 FirmwareOperating system
Affected:< r15a
Xcm20 FirmwareOperating system
Affected:< r15a

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify device model
    Determine if the device is a Hitachi Energy FOX61x (specifically FOX615) or XCM20 device. Check the device label, management interface, or use SNMP/sysinfo queries to confirm the model number.
    Affected if The device is not a FOX61x or XCM20 model, then it is not affected by this specific CVE.
  2. Check firmware version
    Access the device management interface or use firmware version check commands. Compare the installed firmware version against the affected range: versions prior to r15a. Look for version strings like 'r14a', 'r13a', or earlier.
    Affected if Firmware version is r15a or later, the device is not vulnerable. Firmware versions below r15a (such as r14a, r13a) are in the affected range.
  3. Verify TCP port 5558 accessibility
    From an external perspective, run a network scan to check if TCP port 5558 is open and reachable. Use 'nmap -p 5558 <device_ip>' or similar port scanning tool. Also check firewall rules and network segmentation that may block or allow this port.
    Affected if TCP port 5558 is open and reachable from an untrusted network, the device could be exploited. The vulnerability requires this port to be accessible.
  4. Confirm proprietary management protocol status
    Check if the proprietary management protocol is enabled on the device. This may be visible in the device network configuration, service status, or by attempting a connection to port 5558 and observing the protocol response.
    Affected if The proprietary management protocol is active and listening on TCP port 5558, the device is susceptible to the missing handler condition that causes NMS/NE communication disruption.

A device is affected if it is a Hitachi Energy FOX615 or XCM20 running firmware prior to r15a AND has TCP port 5558 with the proprietary management protocol exposed and accessible.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update Hitachi Energy FOX61x and XCM20 firmware to version R15A or later. If immediate patching is not feasible, consider restricting access to TCP port 5558 through network segmentation or firewall rules to reduce attack surface.

Recommended fix High confidence

R15A

  1. 1. Identify the current firmware version of the affected Fox615 or XCM20 device by accessing the device management interface
  2. 2. Download the R15A firmware release from the official ABB (Hitachi Energy) support portal at search.abb.com
  3. 3. Follow the official firmware upgrade procedure documented in the device hardware manual for your specific model
  4. 4. After upgrading, verify the firmware has been successfully applied by checking the device management interface shows version R15A or later

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Fox615 Firmware Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing8.0 h
  • Review / QA4.0 h
30.0 hours of engineering $5,280
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-40334 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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