Siemens SIMATIC S7-1500 TM MFP Use After Free (CVE-2025-21791)

high Tenable OT Security Plugin ID 506424

Synopsis

The remote OT asset is affected by a vulnerability.

Description

In the Linux kernel, the following vulnerability has been resolved:

vrf: use RCU protection in l3mdev_l3_out()

l3mdev_l3_out() can be called without RCU being held:

raw_sendmsg() ip_push_pending_frames() ip_send_skb() ip_local_out()
__ip_local_out() l3mdev_ip_out()

Add rcu_read_lock() / rcu_read_unlock() pair to avoid a potential UAF.

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: 506424

File Name: tenable_ot_siemens_CVE-2025-21791.nasl

Version: 1.1

Type: Remote

Family: Tenable.ot

Published: 10/20/2026

Updated: 10/20/2026

Supported Sensors: Tenable OT Security

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 57.12

CVSS v3

Risk Factor: High

Base Score: 7.8

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

Vulnerability Information

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

Required KB Items: Tenable.ot/Siemens

Exploit Ease: No known exploits are available

Patch Publication Date: 10/13/2026

Vulnerability Publication Date: 10/13/2026

Reference Information

CVE: CVE-2025-21791

CWE: 416

Detections

Analytics