CVE-2025-40940: Siemens SIMATIC Cn 4100 Firmware

Medium severity, CVSS 4.9. EPSS: 0.4% chance of exploitation in the next 30 days.

A vulnerability has been identified in SIMATIC CN 4100 (All versions < V4.0.1). The affected application exhibits inconsistent SNMP behavior, such as unexpected service availability and unreliable configuration handling across protocol versions. This could allow an attacker to access sensitive data, potentially leading to a breach of confidentiality.

Affected products

• Siemens SIMATIC Cn 4100 Firmware: before 4.0.1 (fixed in 4.0.1)

Published 2025-12-09. Last modified 2026-10-07.