Siemens SIMATIC ET 200 Uncontrolled Resource Consumption (CVE-2025-40944)

high Tenable OT Security Plugin ID 505099

Synopsis

The remote OT asset is affected by a vulnerability.

Description

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.

This plugin only works with Tenable.ot.
Please visit https://www.tenable.com/products/tenable-ot for more information.

Solution

Refer to the vendor advisory.

Plugin Details

Severity: High

ID: 505099

File Name: tenable_ot_siemens_CVE-2025-40944.nasl

Version: 1.1

Type: remote

Family: Tenable.ot

Published: 2/10/2026

Updated: 2/10/2026

Supported Sensors: Tenable OT Security

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v3

Risk Factor: High

Base Score: 7.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Vulnerability Information

CPE: cpe:/o:siemens:simatic_et_200mp_im_155-5_pn_hf_firmware:4.2.0, cpe:/o:siemens:simatic_et_200sp_im_155-6_pn_r1_firmware:6.0.1, cpe:/o:siemens:simatic_et_200sp_im_155-6_pn%2f3_hf_firmware:4.2.2, cpe:/o:siemens:siplus_et_200mp_im_155-5_pn_hf_t1_rail_firmware:4.2.0, cpe:/o:siemens:simatic_et_200sp_im_155-6_pn_ha_firmware:1.3, cpe:/o:siemens:siplus_et_200sp_im_155-6_pn_hf_t1_rail_firmware:4.2.0, cpe:/o:siemens:siplus_et_200sp_im_155-6_pn_hf_tx_rail_firmware:4.2.0, cpe:/o:siemens:simatic_et_200sp_im_155-6_mf_hf_firmware, cpe:/o:siemens:siplus_et_200mp_im_155-5_pn_hf_firmware:4.2.0, cpe:/o:siemens:simatic_et_200sp_im_155-6_pn%2f2_hf_firmware:4.2.0, cpe:/o:siemens:siplus_et_200sp_im_155-6_pn_hf_firmware:4.2.0, cpe:/o:siemens:simatic_et_200al_im_157-1_pn_firmware

Required KB Items: Tenable.ot/Siemens

Exploit Ease: No known exploits are available

Patch Publication Date: 1/13/2026

Vulnerability Publication Date: 1/13/2026

Reference Information

CVE: CVE-2025-40944

CWE: 400

ICSA: 26-015-04

Detections

Analytics