Siemens SIMATIC S7-1500 TM MFP Improper Input Validation (CVE-2026-46294)

high Tenable OT Security Plugin ID 506416

Synopsis

The remote OT asset is affected by a vulnerability.

Description

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

dm: fix a buffer overflow in ioctl processing

Tony Asleson (using Claude) found a buffer overflow in dm-ioctl in the function retrieve_status:

1. The code in retrieve_status checks that the output string fits into the output buffer and writes the output string there 2. Then, the code aligns the 'outptr' variable to the next 8-byte boundary:
outptr = align_ptr(outptr);
3. The alignment doesn't check overflow, so outptr could point past the buffer end 4. The 'for' loop is iterated again, it executes:
remaining = len - (outptr - outbuf);
5. If 'outptr' points past 'outbuf + len', the arithmetics wraps around and the variable 'remaining' contains unusually high number 6. With 'remaining' being high, the code writes more data past the end of the buffer

Luckily, this bug has no security implications because:
1. Only root can issue device mapper ioctls 2. The commonly used libraries that communicate with device mapper (libdevmapper and devicemapper-rs) use buffer size that is aligned to 8 bytes - thus, 'outptr = align_ptr(outptr)' can't overshoot the input buffer and the bug can't happen accidentally

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: 506416

File Name: tenable_ot_siemens_CVE-2026-46294.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: 58.14

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-2026-46294

CWE: 20

Detections

Analytics