SIMATIC CN 4100 DoS Vulnerability: CVE-2026-22925 Poses High Risk
A high-severity denial-of-service (DoS) vulnerability, tracked as CVE-2026-22925, has been identified in all versions of Siemens SIMATIC CN 4100 prior to V5.0. According to the National Vulnerability Database, this flaw stems from a resource exhaustion issue, specifically when the industrial control system is barraged with a high volume of TCP SYN packets.
This vulnerability, with a CVSS score of 7.5 (High), allows an unauthenticated attacker to remotely overwhelm system resources. The attacker’s objective is straightforward: render the SIMATIC CN 4100 service unavailable, causing significant operational disruption. It’s a classic SYN flood scenario, but in an ICS context, the implications are far more severe than a typical web server DoS.
For defenders, this is a critical operational technology (OT) concern. Siemens SIMATIC CN 4100 units are often deployed in environments where uptime is paramount. An attacker doesn’t need to breach the perimeter; simply flooding the network segment with SYN packets is enough to take these devices offline. The National Vulnerability Database attributes this to CWE-770, highlighting the underlying issue of improper resource management.
What This Means For You
- If your organization uses Siemens SIMATIC CN 4100, you need to identify all units running versions prior to V5.0 immediately. Prioritize patching to V5.0 or later to mitigate CVE-2026-22925. Furthermore, review your network segmentation and implement robust SYN flood protection measures on firewalls and intrusion prevention systems fronting these critical OT assets.
Related ATT&CK Techniques
🛡️ Detection Rules
2 rules · 6 SIEM formats2 detection rules auto-generated for this incident, mapped to MITRE ATT&CK. Sigma YAML is free — export to any SIEM format via the Intel Bot.
DoS Traffic Pattern Detection
title: DoS Traffic Pattern Detection
id: scw-2026-05-12-1
status: experimental
level: high
description: |
Detects volumetric traffic patterns consistent with denial of service attacks targeting your infrastructure.
author: SCW Feed Engine (auto-generated)
date: 2026-05-12
references:
- https://shimiscyberworld.com/posts/nvd-CVE-2026-22925/
tags:
- attack.impact
- attack.t1499
logsource:
category: firewall
detection:
selection:
dst_port:
- 80
- 443
condition: selection | count(src_ip) by dst_ip > 1000
falsepositives:
- Legitimate activity from CVE-2026-22925
Source: Shimi's Cyber World · License & reuse
Indicators of Compromise
| ID | Type | Indicator |
|---|---|---|
| CVE-2026-22925 | DoS | SIMATIC CN 4100 (All versions < V5.0) |
| CVE-2026-22925 | DoS | Resource exhaustion via high volume of TCP SYN packets |
Written by SCW Vulnerability Desk
Source & Attribution
| Source Platform | NVD |
| Channel | National Vulnerability Database |
| Published | May 12, 2026 at 13:16 UTC |
This content was AI-rewritten and enriched by Shimi's Cyber World based on the original source. All intellectual property rights remain with the original author.
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