Siemens SIMATIC S7-1500 TM MFP Improper Input Validation (CVE-2026-43094)

medium Tenable OT Security Plugin ID 506316

Synopsis

The remote OT asset is affected by a vulnerability.

Description

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

ixgbevf: add missing negotiate_features op to Hyper-V ops table

Commit a7075f501bd3 ('ixgbevf: fix mailbox API compatibility by negotiating supported features') added the .negotiate_features callback to ixgbe_mac_operations and populated it in ixgbevf_mac_ops, but forgot to add it to ixgbevf_hv_mac_ops. This leaves the function pointer NULL on Hyper-V VMs.

During probe, ixgbevf_negotiate_api() calls ixgbevf_set_features(), which unconditionally dereferences hw->mac.ops.negotiate_features().
On Hyper-V this results in a NULL pointer dereference:

BUG: kernel NULL pointer dereference, address: 0000000000000000 [...] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine [...] Workqueue: events work_for_cpu_fn RIP: 0010:0x0 [...] Call Trace:
ixgbevf_negotiate_api+0x66/0x160 [ixgbevf] ixgbevf_sw_init+0xe4/0x1f0 [ixgbevf] ixgbevf_probe+0x20f/0x4a0 [ixgbevf] local_pci_probe+0x50/0xa0 work_for_cpu_fn+0x1a/0x30 [...]

Add ixgbevf_hv_negotiate_features_vf() that returns -EOPNOTSUPP and wire it into ixgbevf_hv_mac_ops. The caller already handles -EOPNOTSUPP gracefully.

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Solution

Refer to the vendor advisory.

Plugin Details

Severity: Medium

ID: 506316

File Name: tenable_ot_siemens_CVE-2026-43094.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: 5

Percentile: 93.15

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-2026-43094

CWE: 20

Detections

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