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750 893 FirmwareOperating system · Wago

CVE-2021-30188

CRITICAL · 9.8 CVSS v3.1 Published 2021-05-25
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
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
CODESYS V2 runtime system SP before 2.4.7.55 has a Stack-based Buffer Overflow.

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 stack-based buffer overflow vulnerability exists in the CODESYS V2 runtime system in versions prior to 2.4.7.55. This memory corruption flaw could allow remote attackers to execute arbitrary code or cause a denial of service condition on affected industrial control systems.

MitigationUpdate CODESYS V2 runtime system to version 2.4.7.55 or later. If immediate patching is not feasible, implement network segmentation and restrict access to the runtime system to trusted IP addresses only.

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
750 893 FirmwareOperating system
Affected:< fw08
750 891 FirmwareOperating system
Affected:< fw08
750 890 FirmwareOperating system
Affected:< fw08
750 889 FirmwareOperating system
Affected:< fw15
750 885 FirmwareOperating system
Affected:< fw15
750 882 FirmwareOperating system
Affected:< fw15
750 881 FirmwareOperating system
Affected:< fw15
750 880 FirmwareOperating system
Affected:< fw16

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
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 controller model
    Locate the device label or check system information to confirm the exact model number (750-880, 750-881, 750-882, 750-885, 750-889, 750-890, 750-891, or 750-893)
    Affected if The model number matches one of the affected Wago 750 series controllers listed in the CVE
  2. Check the CODESYS V2 runtime firmware version
    Access the controller firmware or runtime system information through its management interface or system utilities to retrieve the current firmware version number
    Affected if The installed firmware version cannot be determined or is not documented
  3. Compare firmware version against affected ranges
    Compare your installed firmware version to the affected thresholds: 750-893/891/890 require fw08 or higher, 750-889/885/882/881 require fw15 or higher, 750-880 requires fw16 or higher
    Affected if The firmware version is below the threshold (for example, below fw08 for 750-893, below fw15 for 750-889, below fw16 for 750-880)
  4. Confirm CODESYS V2 runtime is active
    Verify that the CODESYS V2 runtime system is running and accessible on the controller, typically through network service enumeration or runtime status checks
    Affected if The CODESYS V2 runtime is enabled and accessible on the network

You are affected if you have a Wago 750 series controller (880, 881, 882, 885, 889, 890, 891, or 893) running a CODESYS V2 runtime with firmware version below the threshold (fw08, fw15, or fw16 depending on model), and the runtime is actively running.

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 CODESYS V2 runtime system to version 2.4.7.55 or later. If immediate patching is not feasible, implement network segmentation and restrict access to the runtime system to trusted IP addresses only.

Recommended fix High confidence

CODESYS V2 runtime system SP 2.4.7.55 or later; WAGO 750 series firmware: fw08 (for 750-893/891/890), fw15 (for 750-889/885/882/881), fw16 (for 750-880)

  1. 1. Identify the specific 750 series controller model (750-880, 750-881, 750-882, 750-885, 750-889, 750-890, 750-891, or 750-893) in your deployment
  2. 2. Determine the current firmware version installed on the affected controller
  3. 3. Download the latest firmware update from the WAGO website or through your authorized WAGO distributor
  4. 4. For controller models 750-893, 750-891, 750-890: upgrade firmware to version fw08 or later
  5. 5. For controller models 750-889, 750-885, 750-882, 750-881: upgrade firmware to version fw15 or later
  6. 6. For controller model 750-880: upgrade firmware to version fw16 or later
  7. 7. After firmware upgrade, ensure the CODESYS V2 runtime system is updated to SP 2.4.7.55 or later
  8. 8. Verify the updated versions are correctly installed and the controller is functioning properly
Caveat Ensure compatibility of existing CODESYS projects with the new runtime version before deploying to production

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

Fix this in 750 893 Firmware Scoped from the published advisory
  • Consultation8.0 h
  • Implementation4.0 h
  • Testing12.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,840
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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-2021-30188 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
  • 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