PatchSiren cyber security CVE debrief

CVE-2024-42276 Siemens CVE debrief

A vulnerability in the Linux kernel's NVMe PCI driver could allow a local, privileged attacker to cause a denial of service (DoS) condition. The issue stems from a missing condition check in nvme_unmap_data() that fails to verify the existence of mapped data before dereferencing, potentially leading to a NULL pointer dereference. The vulnerability was resolved by ensuring nvme_unmap_data() applies the same conditional logic as nvme_map_data(), which is only called when a request has physical segments. Siemens has identified this vulnerability as affecting the GNU/Linux subsystem of the SIMATIC S7-1500 TM MFP industrial control system. No patch is currently available from Siemens; mitigation relies on restricting access to trusted personnel and running only trusted applications.

Vendor: Siemens
Product: SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
CVSS: MEDIUM 4.4
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 systems with the GNU/Linux subsystem enabled, particularly in industrial and OT environments where high availability is critical. System administrators responsible for securing embedded Linux environments on industrial controllers should prioritize access controls until a patch becomes available.

Technical summary

The vulnerability exists in the nvme-pci driver of the Linux kernel. The function nvme_map_data() is invoked only when a request contains physical segments, but the corresponding nvme_unmap_data() function lacked an equivalent condition check. This inconsistency could result in dereferencing NULL or invalid pointers when unmapping data that was never mapped, leading to a kernel crash and system availability impact. The fix ensures nvme_unmap_data() mirrors the conditional logic of nvme_map_data().

Defensive priority

medium

Recommended defensive actions

Restrict interactive shell access to the GNU/Linux subsystem on affected Siemens SIMATIC S7-1500 TM MFP devices to trusted personnel only
Ensure only applications from trusted sources are built and executed on the affected subsystem
Monitor for kernel updates from Siemens that address this vulnerability in the GNU/Linux subsystem
Apply defense-in-depth strategies for industrial control systems per CISA guidance
Review and implement ICS-CERT recommended practices for securing industrial control environments

Evidence notes

The vulnerability description indicates a resolved Linux kernel issue in the nvme-pci driver where nvme_unmap_data() lacked a condition check present in nvme_map_data(). Siemens CSAF data confirms this affects the SIMATIC S7-1500 TM MFP GNU/Linux subsystem. The CVSS vector AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H indicates local attack vector, low attack complexity, high privileges required, no user interaction, and high availability impact.

Official resources

2024-04-09