Siemens SIMATIC S7-1500 TM MFP Improper Input Validation (CVE-2026-53265)

high Tenable OT Security Plugin ID 506272

Synopsis

The remote OT asset is affected by a vulnerability.

Description

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

dm cache policy smq: check allocation under invalidate lock

commit 2d1f7b65f5de ('dm cache policy smq: fix missing locks in invalidating cache blocks') added mq->lock around the destructive part of smq_invalidate_mapping(), but left the e->allocated check outside the critical section.

That leaves a check-then-act race. Two concurrent invalidators can both observe e->allocated as true before either of them takes mq->lock. The first invalidator that acquires the lock removes the entry from the queues and hash table and then calls free_entry(), which clears e->allocated and puts the entry back on the free list. The second invalidator can then acquire mq->lock and continue with the stale result of the unlocked check.

This can corrupt the SMQ queues or hash table by deleting an entry that is no longer on those structures. It can also hit the allocation check in free_entry() when the same entry is freed again.

Move the allocation check under mq->lock so the predicate and the destructive operations are serialized by the same lock.

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: 506272

File Name: tenable_ot_siemens_CVE-2026-53265.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: 6.9

Percentile: 96.5

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-2026-53265

CWE: 20

Detections

Analytics