Siemens SIMATIC S7-1500 TM MFP Improper Input Validation (CVE-2026-53227)

medium Tenable OT Security Plugin ID 506303

Synopsis

The remote OT asset is affected by a vulnerability.

Description

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

net: openvswitch: fix possible kfree_skb of ERR_PTR

After the patch in the 'Fixes' tag, the allocation of the 'reply' skb can happen either before or after locking the ovs_mutex.

However, error cleanups still follow the classical reversed order, assuming 'reply' is allocated before locking: it is freed after unlocking.

If 'reply' allocation happens after locking the mutex and it fails, 'reply' is left with an ERR_PTR, and execution jumps to the correspondent cleanup stage which will try to free an invalid pointer.

Fix this by setting the pointer to NULL after having saved its error value.

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: 506303

File Name: tenable_ot_siemens_CVE-2026-53227.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: Low

Score: 3

Percentile: 23.75

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_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-2026-53227

CWE: 20

Detections

Analytics