Siemens SIMATIC S7-1500 TM MFP Improper Update of Reference Count (CVE-2026-23296)

medium Tenable OT Security Plugin ID 506420

Synopsis

The remote OT asset is affected by a vulnerability.

Description

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

scsi: core: Fix refcount leak for tagset_refcnt

This leak will cause a hang when tearing down the SCSI host. For example, iscsid hangs with the following call trace:

[130120.652718] scsi_alloc_sdev: Allocation failure during SCSI scanning, some SCSI devices might not be configured

PID: 2528 TASK: ffff9d0408974e00 CPU: 3 COMMAND: 'iscsid' #0 [ffffb5b9c134b9e0] __schedule at ffffffff860657d4 #1 [ffffb5b9c134ba28] schedule at ffffffff86065c6f #2 [ffffb5b9c134ba40] schedule_timeout at ffffffff86069fb0 #3 [ffffb5b9c134bab0] __wait_for_common at ffffffff8606674f #4 [ffffb5b9c134bb10] scsi_remove_host at ffffffff85bfe84b #5 [ffffb5b9c134bb30] iscsi_sw_tcp_session_destroy at ffffffffc03031c4 [iscsi_tcp] #6 [ffffb5b9c134bb48] iscsi_if_recv_msg at ffffffffc0292692 [scsi_transport_iscsi] #7 [ffffb5b9c134bb98] iscsi_if_rx at ffffffffc02929c2 [scsi_transport_iscsi] #8 [ffffb5b9c134bbf0] netlink_unicast at ffffffff85e551d6 #9 [ffffb5b9c134bc38] netlink_sendmsg at ffffffff85e554ef

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: 506420

File Name: tenable_ot_siemens_CVE-2026-23296.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: 23.73

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-2026-23296

CWE: 911

Detections

Analytics