Siemens SIMATIC Devices Incorrect Calculation of Buffer Size (CVE-2022-43945)

medium Tenable OT Security Plugin ID 503556

Synopsis

The remote OT asset is affected by a vulnerability.

Description

The Linux kernel NFSD implementation prior to versions 5.19.17 and 6.0.2 are vulnerable to buffer overflow. NFSD tracks the number of pages held by each NFSD thread by combining the receive and send buffers of a remote procedure call (RPC) into a single array of pages.
A client can force the send buffer to shrink by sending an RPC message over TCP with garbage data added at the end of the message. The RPC message with garbage data is still correctly formed according to the specification and is passed forward to handlers. Vulnerable code in NFSD is not expecting the oversized request and writes beyond the allocated buffer space.

This plugin only works with Tenable.ot.
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Solution

Refer to the vendor advisory.

Plugin Details

Severity: Medium

ID: 503556

Version: 1.2

Type: remote

Family: Tenable.ot

Published: 10/27/2025

Updated: 10/29/2025

Supported Sensors: Tenable OT Security

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v3

Risk Factor: Medium

Base Score: 6.5

Vector: CVSS:3.0/AV:N/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: 4/9/2024

Vulnerability Publication Date: 10/31/2022

Reference Information

CVE: CVE-2022-43945

CWE: 131

Detections

Analytics