dbcve.org
Improper Input ValidationWeakness · CWE-20

CVE-2020-37216

HIGH · 7.5 CVSS v3.1 Published 2026-04-03
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
Hirschmann HiOS devices versions prior to 08.1.00 and 07.1.01 contain a denial of service vulnerability in the EtherNet/IP stack where improper handling of packet length fields allows remote attackers to crash or hang the device. Attackers can send specially crafted UDP EtherNet/IP packets with a length value larger than the actual packet size to render the device inoperable.

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 · high confidence

Hirschmann HiOS devices prior to versions 08.1.00 and 07.1.01 contain a denial of service vulnerability in the EtherNet/IP stack caused by improper validation of packet length fields. Attackers can send specially crafted UDP EtherNet/IP packets containing a length value larger than the actual packet size, causing the device to crash or hang and become inoperable.

MitigationApply vendor-supplied firmware updates to version 08.1.00 or 07.1.01. Until patched, restrict network access to EtherNet/IP UDP ports and implement network segmentation to minimize exposure.

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

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 Hirschmann HiOS device
    Check device model via web interface, CLI (show system info), or SNMP sysDescr query. Look for 'Hirschmann' and 'HiOS' in the device identification.
    Affected if Device is not a Hirschmann HiOS product, then it is not affected by this specific vulnerability.
  2. Check HiOS version number
    Access device CLI and run 'show version' or check via web interface System > Software Info. Compare the displayed version to the fixed releases (07.1.01 or 08.1.00 and later).
    Affected if Version is older than 07.1.01 or 08.1.00, or if the version cannot be determined and the device is confirmed as HiOS.
  3. Verify EtherNet/IP feature is enabled
    Access device web interface or CLI. Navigate to Ethernet/IP configuration (typically under Protocols > EtherNet/IP or Industrial Protocols). Check if EtherNet/IP is actively enabled.
    Affected if EtherNet/IP protocol stack is enabled and running on the device.
  4. Confirm UDP port 2222 exposure
    Perform a UDP port scan targeting port 2222 from an external host, or check device firewall/access control lists. Use command: 'nmap -sU -p 2222 <device_ip>' or check device network configuration for allowed UDP traffic on port 2222.
    Affected if UDP port 2222 (EtherNet/IP) is exposed to untrusted network segments.

If the device is a Hirschmann HiOS version prior to 07.1.01 or 08.1.00 with EtherNet/IP enabled and UDP port 2222 accessible from untrusted networks, the environment is affected by this CVE.

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

Apply vendor-supplied firmware updates to version 08.1.00 or 07.1.01. Until patched, restrict network access to EtherNet/IP UDP ports and implement network segmentation to minimize exposure.

Recommended fix Moderate confidence

HiOS 08.1.00 or HiOS 07.1.01 (depending on device model - refer to Belden compatibility matrix)

  1. Identify the specific Hirschmann HiOS device model in use
  2. Determine the current firmware version installed on the device
  3. Check the hardware compatibility matrix to determine whether to upgrade to HiOS 08.1.00 or 07.1.01 based on the device model
  4. Download the appropriate firmware version from the Belden/Hirschmann support portal (assets.belden.com)
  5. Review the firmware release notes for any special upgrade instructions or prerequisites
  6. Back up the current device configuration
  7. Upload the new firmware file via the device web interface or CLI using the firmware update function
  8. Verify the firmware upgrade was successful and the device is operational

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

Have this fixed Scoped from the published advisory
  • Consultation3.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,770
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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-2020-37216 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

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