PatchSiren cyber security CVE debrief

CVE-2024-35944 Siemens CVE debrief

A vulnerability in the VMCI (Virtual Machine Communication Interface) kernel module, specifically in the `dg_dispatch_as_host()` function, could allow a local attacker to trigger a memcpy run-time warning condition. The issue stems from improper memory handling during datagram dispatch operations in host mode. Successful exploitation could result in denial of service conditions on affected systems. The vulnerability has a CVSS 3.1 score of 5.5 (MEDIUM severity) with a local attack vector, low attack complexity, and low privileges required. No confidentiality or integrity impact is indicated, but availability impact is rated as high.

Vendor: Siemens
Product: SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
CVSS: MEDIUM 5.5
CISA KEV: Not listed in stored evidence
Original CVE published: 2024-04-09
Original CVE updated: 2026-05-14
Advisory published: 2024-04-09
Advisory updated: 2026-05-14

Who should care

Organizations operating Siemens SIMATIC S7-1500 TM MFP industrial controllers with the GNU/Linux subsystem enabled should prioritize this vulnerability. System administrators responsible for OT/ICS environments, security teams managing industrial control systems, and personnel with interactive shell access to these devices are directly affected. Given the local attack vector, insider threats or compromised accounts with low privileges pose the primary risk.

Technical summary

The vulnerability exists in the VMCI (Virtual Machine Communication Interface) kernel module's `dg_dispatch_as_host()` function. The issue involves a memcpy() run-time warning that can be triggered, potentially leading to denial of service conditions. The VMCI module facilitates communication between virtual machines and the host system. The vulnerability is classified under CWE-787 (Out-of-bounds Write). The affected component is the GNU/Linux subsystem of the Siemens SIMATIC S7-1500 TM MFP, an industrial automation controller. No patch is currently available from the vendor.

Defensive priority

medium

Recommended defensive actions

Restrict interactive shell access to the GNU/Linux subsystem to trusted personnel only
Implement application whitelisting - only build and run applications from trusted sources
Monitor for anomalous process behavior or unexpected system crashes on affected devices
Apply vendor patches when Siemens releases a fix for this vulnerability
Segment industrial control networks to limit lateral movement opportunities
Review and implement CISA ICS recommended practices for defense in depth

Evidence notes

The vulnerability description indicates this is a VMCI kernel module issue in the `dg_dispatch_as_host()` function related to memcpy() operations. The CVSS vector (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H) confirms local attack vector with high availability impact. The affected product is specifically the GNU/Linux subsystem of the Siemens SIMATIC S7-1500 TM MFP industrial controller.

Official resources

CVE-2024-35944 was published on April 9, 2024, and last modified on May 14, 2026. The vulnerability was disclosed through CISA's ICS advisory ICSA-24-102-01, which has undergone multiple revisions adding additional CVEs through September 9,