CVE-2025-40795

Critical

Published: 09 September 2025

Published

09 September 2025

Modified

14 October 2025

KEV Added

—

Patch

—

CVSS Score 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Score 0.0027 50.0th percentile

Risk Priority 20 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-40795 is a critical-severity Stack-based Buffer Overflow (CWE-121) vulnerability in Siemens Simatic Pcs Neo. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 50.0th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-16 (Memory Protection).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploit Public-Facing Application (T1190). What defenders deploy: see the NIST 800-53 controls recommended below.

Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

SI-2 Flaw Remediation good match

prevent

Requires timely remediation of the identified stack-based buffer overflow vulnerability through patching to UMC V2.15.1.3 or later, directly eliminating the flaw.

SI-16 Memory Protection good match

prevent

Implements memory protection mechanisms such as stack canaries, ASLR, and non-executable memory stacks that directly thwart exploitation of stack-based buffer overflows.

SI-10 Information Input Validation good match

prevent

Enforces validation of inputs to the UMC component to prevent buffer overflows from malformed or oversized data processed by unauthenticated remote attackers.

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

Why these techniques?

Remote unauthenticated stack buffer overflow enabling arbitrary code execution on a network-accessible industrial management component directly maps to exploitation of public-facing applications for initial access.

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

NVD Description

A vulnerability has been identified in SIMATIC PCS neo V4.1 (All versions), SIMATIC PCS neo V5.0 (All versions), SIMATIC PCS neo V6.0 (All versions), User Management Component (UMC) (All versions < V2.15.1.3). Affected products contain a stack-based buffer overflow vulnerability…

in the integrated UMC component. This could allow an unauthenticated remote attacker to execute arbitrary code or to cause a denial of service condition.

Deeper analysisAI

CVE-2025-40795 is a stack-based buffer overflow vulnerability (CWE-121) affecting the integrated User Management Component (UMC) in SIMATIC PCS neo versions V4.1, V5.0, and V6.0 (all versions), as well as standalone UMC versions prior to V2.15.1.3. Published on September 9, 2025, the flaw resides in the UMC component common to these Siemens industrial automation products, earning a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), indicating critical severity.

An unauthenticated remote attacker can exploit this vulnerability over the network with low complexity and no user interaction required. Successful exploitation could enable arbitrary code execution on the affected system or trigger a denial-of-service condition, potentially disrupting industrial control operations.

Siemens has published security advisory SSA-722410, available at https://cert-portal.siemens.com/productcert/html/ssa-722410.html, which provides details on mitigation, including updating to UMC V2.15.1.3 or later where applicable. Security practitioners should consult the advisory for version-specific patching instructions and workarounds for unpatchable systems.