Siemens SIMATIC Pn/mf Coupler vulnerabilities

2 CVEs affecting Siemens SIMATIC Pn/mf Coupler, 0 known to be exploited (CISA KEV), with EPSS scores. Latest: CVE-2025-40944, published 2026-01-13.

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Known exploited (CISA KEV) first, then by EPSS exploit probability.

• CVE-2025-40820, published 2025-12-09. High severity, CVSS 7.5. EPSS: 0.5% chance of exploitation in the next 30 days. Affected products do not properly enforce TCP sequence number validation in specific scenarios but accept values within a broad range. This could allow an unauthenticated remote attacker e.g. to…
• CVE-2025-40944, published 2026-01-13. High severity, CVSS 7.5. EPSS: 0.4% chance of exploitation in the next 30 days. A vulnerability has been identified in SIMATIC ET 200AL IM 157-1 PN (6ES7157-1AB00-0AB0) (All versions), SIMATIC ET 200MP IM 155-5 PN HF (6ES7155-5AA00-0AC0) (All versions >= V4.2.0), SIMATIC ET…