Siemens SIMATIC Devices Improper Input Validation (CVE-2025-21795)

medium Tenable OT Security Plugin ID 503727

Synopsis

The remote OT asset is affected by a vulnerability.

Description

NFSD: hang in nfsd4_shutdown_callback. If nfs4_client is in courtesy state then there is no point to send the callback. This causes nfsd4_shutdown_callback to hang since cl_cb_inflight is not 0. This hang lasts about 15 minutes until TCP notifies NFSD that the connection was dropped.

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: Medium

ID: 503727

Version: 1.2

Type: remote

Family: Tenable.ot

Published: 10/27/2025

Updated: 10/29/2025

Supported Sensors: Tenable OT Security

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

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, cpe:/o:siemens:simatic_s7-1500_tm_mfp

Required KB Items: Tenable.ot/Siemens

Exploit Ease: No known exploits are available

Patch Publication Date: 4/9/2024

Vulnerability Publication Date: 4/9/2024

Reference Information

CVE: CVE-2025-21795

CWE: 20

Detections

Analytics