Siemens SIMATIC S7-1500 TM MFP Improper Validation of Specified Index, Position, or Offset in Input (CVE-2026-23388)

high Tenable OT Security Plugin ID 506264

Synopsis

The remote OT asset is affected by a vulnerability.

Description

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

Squashfs: check metadata block offset is within range

Syzkaller reports a 'general protection fault in squashfs_copy_data'

This is ultimately caused by a corrupted index look-up table, which produces a negative metadata block offset.

This is subsequently passed to squashfs_copy_data (via squashfs_read_metadata) where the negative offset causes an out of bounds access.

The fix is to check that the offset is within range in squashfs_read_metadata. This will trap this and other cases.

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: 506264

File Name: tenable_ot_siemens_CVE-2026-23388.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: 4.3

Percentile: 53.47

CVSS v3

Risk Factor: High

Base Score: 7

Vector: CVSS:3.0/AV:L/AC:H/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-2026-23388

CWE: 1285

Detections

Analytics