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Vulnerability · Published Jan 13, 2026 · Assigned by siemens

CVE-2025-40944

High 7.5

In plain English

A high-severity uncontrolled resource consumption in SIMATIC ET 200AL IM 157-1 PN from Siemens. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 38% of all known vulnerabilities).

Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.4%top 62.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

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 200SP IM 155-6 MF HF (6ES7155-6MU00-0CN0) (All versions), SIMATIC ET 200SP IM 155-6 PN HA (incl. SIPLUS variants) (All versions < V1.3), SIMATIC ET 200SP IM 155-6 PN R1 (6ES7155-6AU00-0HM0) (All versions < V6.0.1), SIMATIC ET 200SP IM 155-6 PN/2 HF (6ES7155-6AU01-0CN0) (All versions >= V4.2.0 < V4.2.5), SIMATIC ET 200SP IM 155-6 PN/3 HF (6ES7155-6AU30-0CN0) (All versions < V4.2.2), SIMATIC PN/MF Coupler (6ES7158-3MU10-0XA0) (All versions), SIMATIC PN/PN Coupler (6ES7158-3AD10-0XA0) (All versions < V6.0.0), SIPLUS ET 200MP IM 155-5 PN HF (6AG1155-5AA00-2AC0) (All versions >= V4.2.0), SIPLUS ET 200MP IM 155-5 PN HF (6AG1155-5AA00-7AC0) (All versions >= V4.2.0), SIPLUS ET 200MP IM 155-5 PN HF T1 RAIL (6AG2155-5AA00-1AC0) (All versions >= V4.2.0), SIPLUS ET 200SP IM 155-6 PN HF (6AG1155-6AU01-2CN0) (All versions >= V4.2.0 < V4.2.5), SIPLUS ET 200SP IM 155-6 PN HF (6AG1155-6AU01-7CN0) (All versions >= V4.2.0 < V4.2.5), SIPLUS ET 200SP IM 155-6 PN HF T1 RAIL (6AG2155-6AU01-1CN0) (All versions >= V4.2.0 < V4.2.5), SIPLUS ET 200SP IM 155-6 PN HF TX RAIL (6AG2155-6AU01-4CN0) (All versions >= V4.2.0 < V4.2.5), SIPLUS NET PN/PN Coupler (6AG2158-3AD10-4XA0) (All versions < V6.0.0). Affected devices do not properly handle S7 protocol session disconnect requests. When receiving a valid S7 protocol Disconnect Request (COTP DR TPDU) on TCP port 102, the devices enter an improper session state. This could allow an attacker to cause the device to become unresponsive, leading to a denial-of-service condition that requires a power cycle to restore normal operation.

Affected products (as reported)

VendorProductVersions
Siemens SIMATIC ET 200AL IM 157-1 PN 0 – before *
Siemens SIMATIC ET 200MP IM 155-5 PN HF V4.2.0 – before *
Siemens SIMATIC ET 200SP IM 155-6 MF HF 0 – before *
Siemens SIMATIC ET 200SP IM 155-6 PN HA (incl. SIPLUS variants) 0 – before V1.3
Siemens SIMATIC ET 200SP IM 155-6 PN R1 0 – before V6.0.1
Siemens SIMATIC ET 200SP IM 155-6 PN/2 HF V4.2.0 – before V4.2.5
Siemens SIMATIC ET 200SP IM 155-6 PN/3 HF 0 – before V4.2.2
Siemens SIMATIC PN/MF Coupler 0 – before *
Siemens SIMATIC PN/PN Coupler 0 – before V6.0.0
Siemens SIPLUS ET 200MP IM 155-5 PN HF V4.2.0 – before *
Siemens SIPLUS ET 200MP IM 155-5 PN HF V4.2.0 – before *
Siemens SIPLUS ET 200MP IM 155-5 PN HF T1 RAIL V4.2.0 – before *
Siemens SIPLUS ET 200SP IM 155-6 PN HF V4.2.0 – before V4.2.5
Siemens SIPLUS ET 200SP IM 155-6 PN HF V4.2.0 – before V4.2.5
Siemens SIPLUS ET 200SP IM 155-6 PN HF T1 RAIL V4.2.0 – before V4.2.5
Siemens SIPLUS ET 200SP IM 155-6 PN HF TX RAIL V4.2.0 – before V4.2.5
Siemens SIPLUS NET PN/PN Coupler 0 – before V6.0.0

Weakness: CWE-400 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References