Denial-of-Service Vulnerability in Siemens SIMATIC ET 200 Products
CVE-2025-40944

8.7HIGH

Key Information:

Vendor

Siemens
Status
Simatic Et 200al Im 157-1 Pn
Simatic Et 200mp Im 155-5 Pn Hf
Simatic Et 200sp Im 155-6 Mf Hf
Simatic Et 200sp Im 155-6 Pn Ha (incl. Siplus Variants)
Vendor
CVE Published:
13 January 2026

What is CVE-2025-40944?

A vulnerability in Siemens SIMATIC ET 200 products has been identified where affected devices fail to properly manage S7 protocol session disconnect requests. When a valid Disconnect Request is received on TCP port 102, these devices may enter an improper session state, leading to a denial-of-service condition. This issue necessitates a power cycle to restore normal operations, potentially impacting critical functions and uptime.

Affected Version(s)

SIMATIC ET 200AL IM 157-1 PN 0

SIMATIC ET 200MP IM 155-5 PN HF V4.2.0

SIMATIC ET 200SP IM 155-6 MF HF 0

References

https://cert-portal.siemens.com/productcert/html/ssa-6747...

CVSS V4

Score:
8.7
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

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