# CVE-2026-22925: Siemens SIMATIC CN 4100 resource exhaustion via TCP SYN flood

Source: https://junglewise.ai/threats/cve-2026-22925-siemens-simatic-cn-4100-resource-exhaustion-via-tcp-syn-flood  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-12. Updated: 2026-06-29  
License: CC BY 4.0 with a link back

CVE-2026-22925 · Severity: high · CVSS 7.5 · Published 2026-05-12

The SIMATIC CN 4100 is a communication node used to integrate third-party systems into industrial process control environments. A vulnerability in this device allows a remote attacker to overwhelm its processing capabilities by sending a high volume of specific network traffic (TCP SYN packets). If exploited, this would cause the device to become unresponsive, potentially disrupting industrial operations and communication between connected systems.

Technologies: [Siemens SIMATIC CN 4100](https://junglewise.ai/threats/technologies/simatic-cn-4100), [Siemens Simatic Cn 4100 Firmware](https://junglewise.ai/threats/technologies/simatic-cn-4100-firmware). Vendors: [Siemens](https://junglewise.ai/threats/vendors/siemens).

## Quick answers

**Is CVE-2026-22925 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-22925 being exploited in the wild.

**How severe is CVE-2026-22925?** High severity, with a CVSS score of 7.5, published 12 May 2026.

**Which products and versions are affected?** Siemens SIMATIC CN 4100 All versions < V5.0.

**Is there a fix for CVE-2026-22925?** A patch was published on 2026-05-12: Siemens released version V5.0 to address the issue Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-22925 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-22925?** Check whether you run Siemens SIMATIC CN 4100 or Siemens Simatic Cn 4100 Firmware at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The SIMATIC CN 4100 (versions prior to V5.0) is susceptible to a resource exhaustion vulnerability (CWE-770) triggered by a TCP SYN flood attack. An unauthenticated remote attacker can exploit this by sending a high volume of TCP SYN packets to the device, exhausting system resources and rendering the communication service unavailable. This results in a denial-of-service (DoS) condition. The vulnerability is addressed in firmware version V5.0. Security engineers are advised to update affected hardware and implement network-level protections to throttle or block suspicious TCP traffic.

## Affected products

- Siemens SIMATIC CN 4100 All versions < V5.0

## Timeline

- 2026-05-12: disclosed: Initial advisory publication by Siemens
- 2026-05-12: patched: Siemens released version V5.0 to address the issue

## References

- [https://cert-portal.siemens.com/productcert/html/ssa-032379.html](https://cert-portal.siemens.com/productcert/html/ssa-032379.html)

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