Simatic Cn 4100 FirmwareOperating system · Siemens

CVE-2026-22924

CRITICAL · 9.1 CVSS v3.1 Published 2026-05-12
Fix available
A fix is available. Upgrade to 5.0 or later.
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
A vulnerability has been identified in SIMATIC CN 4100 (All versions < V5.0). The affected application does not properly restrict unauthenticated connections and is susceptible to resource exhaustion conditions. This could allow an attacker to disrupt normal operations or perform unauthorized actions, potentially impacting system availability and integrity.

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

The vulnerability exists in SIMATIC CN 4100 devices running versions prior to V5.0. The application fails to properly restrict unauthenticated network connections, combined with susceptibility to resource exhaustion conditions. This allows remote attackers to consume system resources and potentially perform unauthorized actions, impacting both availability and integrity.

MitigationPrimary remediation is to upgrade SIMATIC CN 4100 to version V5.0 or later. Additionally, implement network segmentation and firewall rules to restrict unauthorized connections to the device until the upgrade can be applied.

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
Simatic Cn 4100 FirmwareOperating system
Affected:< 5.0

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
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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 device model
    Access the device web interface or use SNMP/SSH to query the device and confirm it is a Siemens SIMATIC CN 4100 device. Check the device identification or system information page.
    Affected if The device is not a SIMATIC CN 4100, then this CVE does not apply.
  2. Check the firmware version
    Access the device web interface, typically under System > Device Information or similar, or use the device's CLI to run a version display command (such as 'show version' or via the web admin panel). Compare the displayed firmware version against V5.0.
    Affected if The installed firmware version is earlier than V5.0 (for example, V4.x or earlier).
  3. Verify network exposure of management interfaces
    Use network scanning tools (such as nmap) to identify open ports on the device, particularly ports associated with web administration (80/443), SSH (22), or other management services. Check if these interfaces are reachable from untrusted networks.
    Affected if Management interfaces are exposed to untrusted networks without firewall protection, and the firmware is below V5.0.
  4. Check for unusual network connections or resource usage
    Monitor the device's network connection tables, check for a high number of concurrent connections, or review any available logging for repeated connection attempts from external sources.
    Affected if There is an unusually high number of network connections or evidence of resource exhaustion, and the firmware version is below V5.0.

The environment is affected if the SIMATIC CN 4100 device is running firmware earlier than V5.0 and has management interfaces accessible from 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 5.0 or later
Fixed in 5.0
Interim mitigation

Primary remediation is to upgrade SIMATIC CN 4100 to version V5.0 or later. Additionally, implement network segmentation and firewall rules to restrict unauthorized connections to the device until the upgrade can be applied.

Recommended fix High confidence

V5.0

  1. 1. Identify the current firmware version of the SIMATIC CN 4100 device by accessing the device management interface or using Siemens engineering tools.
  2. 2. Download the V5.0 firmware update from the Siemens Industry Online Support portal (support.industry.siemens.com) or contact Siemens customer support.
  3. 3. Review the firmware release notes and update instructions provided by Siemens for any specific prerequisites or注意事项.
  4. 4. Create a backup of the current device configuration before proceeding with the firmware update.
  5. 5. Apply the V5.0 firmware update following Siemens' recommended procedures for industrial device firmware updates, typically via the device's web interface, TIA Portal, or SIMATIC Management Console.
  6. 6. After the update completes, verify the device is running firmware V5.0 and confirm normal operation.
  7. 7. Verify that the previously vulnerable unauthenticated access vectors are now properly restricted.
Caveat Industrial firmware upgrades may require validation in a test environment first; ensure compatibility with existing control system configurations before deploying to production

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

Fix this in Simatic Cn 4100 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
Get the upgrade done

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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-2026-22924 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