Siemens SIMATIC S7-1500 Improper Input Validation (CVE-2025-21724)

medium Tenable OT Security Plugin ID 503910

Synopsis

The remote OT asset is affected by a vulnerability.

Description

iommufd/iova_bitmap: Fix shift-out-of-bounds in iova_bitmap_offset_to_index(). Resolve a UBSAN shift-out-of-bounds issue in iova_bitmap_offset_to_index() where shifting the constant 1 (of type int) by bitmap->mapped.pgshift (an unsigned long value) could result in undefined behavior. The constant 1 defaults to a 32-bit int, and when pgshift exceeds 31 (e.g., pgshift = 63) the shift operation overflows, as the result cannot be represented in a 32-bit type.

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

Solution

The following text was originally created by the Cybersecurity and Infrastructure Security Agency (CISA). The original can be found at CISA.gov.

Siemens is preparing fixed versions and reports that currently, no fix is available.

As a general security measure, Siemens recommends protecting network access to devices with appropriate mechanisms. To operate the devices in a protected IT environment, Siemens recommends configuring the environment according to Siemens' operational guidelines for industrial security and following recommendations in the product manuals.

Additional information on industrial security by Siemens can be found on the Siemens industrial security webpage

For more information see the associated Siemens security advisory SSA-082556 in HTML and CSAF.

Plugin Details

Severity: Medium

ID: 503910

File Name: tenable_ot_siemens_CVE-2025-21724.nasl

Version: 1.2

Type: remote

Family: Tenable.ot

Published: 11/13/2025

Updated: 2/14/2026

Supported Sensors: Tenable OT Security

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v3

Risk Factor: Medium

Base Score: 5.5

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

Vulnerability Information

CPE: cpe:/o:siemens:simatic_s7-1500_cpu_firmware:3.1.5, cpe:/o:siemens:siplus_s7-1500_cpu_firmware:3.1.5

Required KB Items: Tenable.ot/Siemens

Exploit Ease: No known exploits are available

Patch Publication Date: 6/10/2025

Vulnerability Publication Date: 6/10/2025

Reference Information

CVE: CVE-2025-21724

CWE: 20

ICSA: 23-348-10, 25-162-05

Detections

Analytics