PatchSiren cyber security CVE debrief

CVE-2024-50134 Siemens CVE debrief

A field-spanning write error in the Linux kernel's drm/vboxvideo driver, affecting the vbva_mouse_pointer_shape structure, has been resolved. The vulnerability stemmed from a fake variable-length array (VLA) at the end of the structure that triggered memcpy safety checks. The fix replaces this with a proper VLA declaration. Siemens has identified this as affecting the GNU/Linux subsystem of the SIMATIC S7-1500 TM MFP industrial control product. No patch is currently available from the vendor; mitigations focus on restricting access to trusted personnel and ensuring only trusted applications are executed.

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

Industrial control system operators using Siemens SIMATIC S7-1500 TM MFP with the GNU/Linux subsystem enabled; OT security teams managing manufacturing or process control environments; asset owners responsible for patching Linux-based embedded systems in critical infrastructure

Technical summary

The vulnerability exists in the drm/vboxvideo driver within the Linux kernel, specifically in the vbva_mouse_pointer_shape structure. The original implementation used a fake variable-length array (VLA) at the structure's end, which caused memcpy operations to trigger field-spanning write detection errors. The kernel fix replaces this with a legitimate VLA declaration. The issue affects the GNU/Linux subsystem of Siemens SIMATIC S7-1500 TM MFP industrial controllers. The CVSS vector (AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H) indicates a local attack vector requiring low privileges, with high availability impact but no confidentiality or integrity impact. The source notes that the original buffer length calculation appears to be 4 bytes oversized, though this behavior was preserved in the fix.

Defensive priority

medium

Recommended defensive actions

Restrict interactive shell access to the GNU/Linux subsystem of affected Siemens SIMATIC S7-1500 TM MFP devices to trusted personnel only
Ensure only applications from trusted sources are built and executed on affected systems
Monitor for vendor security advisories from Siemens regarding patch availability for SSA-265688
Review and apply CISA ICS recommended practices for defense-in-depth strategies
Assess operational technology network segmentation to limit potential local attack vectors

Evidence notes

CVE published 2024-04-09. CISA CSAF advisory ICSA-24-102-01 first published same date, with multiple subsequent releases adding related CVEs through 2025-09-09. Siemens advisory SSA-265688 cross-referenced. CVSS 5.5 (MEDIUM) per source, vector AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H indicating local attack vector with low complexity, low privileges required, and high availability impact.

Official resources

public