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750 8100 FirmwareOperating system · Wago

CVE-2021-34568

HIGH · 7.5 CVSS v3.1 Published 2022-11-09
Fix available
A fix is available. Upgrade to 18 or later.
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
In WAGO I/O-Check Service in multiple products an unauthenticated remote attacker can send a specially crafted packet containing OS commands to provoke a denial of service.

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

WAGO I/O-Check Service contains a vulnerability allowing unauthenticated remote attackers to send specially crafted packets containing OS commands, triggering a denial of service condition.

MitigationRestrict network access to the I/O-Check Service using firewalls or network segmentation; isolate affected devices from untrusted networks; apply vendor patches when available.

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
750 8100 FirmwareOperating system
Affected:< 18= 18
750 8101 FirmwareOperating system
Affected:< 18= 18
750 8101\/025 000 FirmwareOperating system
Affected:< 18= 18
750 8102 FirmwareOperating system
Affected:< 18= 18
750 8102\/025 000 FirmwareOperating system
Affected:< 18= 18
750 8202 FirmwareOperating system
Affected:< 18= 18
750 8202\/000 011 FirmwareOperating system
Affected:< 18= 18
750 8202\/000 012 FirmwareOperating system
Affected:< 18= 18

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 the WAGO device model
    Access the device's web interface, administrative console, or check the device label to confirm it is a WAGO 750 series controller (e.g., 750-8100, 750-8101, 750-8102, 750-8202).
    Affected if The device is a WAGO 750 series controller from the list in the CVE.
  2. Check the installed firmware version
    Log into the device's web interface or administrative panel and navigate to the firmware or system information section. Record the firmware version number.
    Affected if The firmware version is less than 18 or exactly version 18.
  3. Verify I/O-Check Service status
    Access the device configuration and check whether the I/O-Check Service (IO-Check daemon) is enabled and running. This may be visible in the services list or network configuration area of the administrative interface.
    Affected if The I/O-Check Service is enabled and running on the device.
  4. Check network exposure of the service
    Review firewall rules, network configuration, or port scans to determine if the I/O-Check Service ports (typically UDP/TCP ports associated with the service) are exposed to untrusted networks or the internet.
    Affected if The I/O-Check Service ports are accessible from untrusted network segments or directly from the internet.

You are affected if the device is a WAGO 750 series model with firmware version 18 or lower, and the I/O-Check Service is enabled and exposed to untrusted networks.

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
Upgrade available Upgrade to 18 or later
Fixed in 18
Interim mitigation

Restrict network access to the I/O-Check Service using firewalls or network segmentation; isolate affected devices from untrusted networks; apply vendor patches when available.

Recommended fix Moderate confidence

Firmware version 19 or later (any version > 18)

  1. Identify the specific WAGO I/O-Check device model from the affected product list (750 8100, 750 8101, 750 8101/025 000, 750 8102, 750 8102/025 000, 750 8202, 750 8202/000 011, or 750 8202/000 012)
  2. Check the current firmware version of the device through the WAGO management interface or IO-Check software
  3. Download the firmware version 19 or later from the official WAGO download portal at wago.com or through your WAGO support channel
  4. Follow the standard WAGO firmware update procedure: backup the current configuration, upload the new firmware via Ethernet/USB, verify the update, and restore configuration if needed
  5. After upgrade, verify that the I/O-Check Service accepts normal operational traffic without DoS conditions
Caveat Review WAGO release notes for version 19 to check for any configuration or feature changes that may require adjustment in your system

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

Fix this in 750 8100 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA3.0 h
21.0 hours of engineering $3,680
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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-2021-34568 in production — separate from our analysis above.

No notes yet

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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
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data