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PatchSiren cyber security CVE debrief

CVE-2024-49878 Siemens CVE debrief

A vulnerability in the Linux kernel's CXL (Compute Express Link) memory driver affects Siemens industrial networking products running SINEC OS. The flaw stems from improper resource hierarchy handling in drivers/dax/kmem.c, where add_memory_driver_managed() creates a nested resource structure during CXL memory onlining. This causes region_intersects() to fail when locating System RAM resources, as it expects these resources at the top level of iomem_resource rather than as descendants of CXL Window resources. The vulnerability can lead to denial of service conditions on affected systems. Siemens has released firmware updates to address this issue in affected RUGGEDCOM and SCALANCE product families.

Vendor
Siemens
Product
RUGGEDCOM RST2428P (6GK6242-6PA00)
CVSS
MEDIUM 5.5
CISA KEV
Not listed in stored evidence
Original CVE published
2025-08-12
Original CVE updated
2026-02-25
Advisory published
2025-08-12
Advisory updated
2026-02-25

Who should care

Organizations operating Siemens RUGGEDCOM RST2428P, SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500, or SCALANCE XCM-/XRM-/XCH-/XRH-300 family industrial networking devices in critical infrastructure environments, particularly those utilizing CXL memory expansion capabilities.

Technical summary

The vulnerability exists in the Linux kernel's DAX kmem driver (drivers/dax/kmem.c), which is used when onlining CXL memory. The function add_memory_driver_managed() creates a resource hierarchy where 'System RAM (kmem)' becomes a child of 'CXL Window X' rather than a direct child of iomem_resource. This violates assumptions in region_intersects(), which expects all System RAM resources to be at the top level of the resource tree. The mismatch can cause memory region intersection checks to fail, potentially leading to system instability or denial of service. The flaw is classified as CWE-20 (Improper Input Validation) and carries a CVSS 3.1 score of 5.5 (Medium severity) with local attack vector, low attack complexity, and high availability impact.

Defensive priority

medium

Recommended defensive actions

  • Apply vendor-provided firmware updates to V3.2 or later for affected RUGGEDCOM RST2428P and SCALANCE XCM-/XRM-/XCH-/XRH-300 family devices
  • For SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family devices, consult Siemens ProductCERT advisory SSA-355557 for specific configuration guidance and update instructions
  • Implement network segmentation for industrial control systems to limit exposure of affected devices
  • Monitor Siemens ProductCERT security advisories for additional updates or clarifications
  • Follow CISA ICS recommended practices for defense-in-depth strategies in industrial control environments

Evidence notes

Vulnerability description and affected product information sourced from CISA CSAF advisory ICSA-25-226-07, which references Siemens ProductCERT advisory SSA-355557. CVSS 3.1 vector confirms local attack vector with low attack complexity and high availability impact.

Official resources

public