PatchSiren

PatchSiren cyber security CVE debrief

CVE-2024-35247 Siemens CVE debrief

CVE-2024-35247 is a Linux kernel vulnerability in the FPGA region subsystem that could lead to a null pointer dereference during FPGA programming operations. The issue stems from the fpga region implementation assuming that low-level modules register a driver for the parent device and use its owner pointer for module reference counting. When the parent device lacks a driver, this assumption fails, potentially causing system instability during region acquisition for programming. The vulnerability was resolved by adding an explicit module owner pointer to the fpga_region structure and modifying registration functions to properly handle module reference counting. Siemens has identified this vulnerability as affecting certain industrial networking products, with a vendor fix available requiring update to version 3.1 or later.

Vendor
Siemens
Product
RUGGEDCOM RST2428P (6GK6242-6PA00)
CVSS
NONE
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 SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family, SCALANCE XCM-/XRM-/XCH-/XRH-300 family, or RUGGEDCOM RST2428P industrial networking equipment; industrial control system operators utilizing FPGA-based programmable logic; Linux kernel maintainers and embedded systems developers working with FPGA subsystems

Technical summary

The vulnerability exists in the Linux kernel's FPGA region management code where the fpga_region structure relies on the parent device's driver owner pointer for module reference counting. When no driver is registered for the parent device, attempting to acquire the region during FPGA programming triggers a null pointer dereference. The resolution adds an explicit 'owner' field to fpga_region, modifies registration functions to accept an owner module parameter, and provides compatibility macros to maintain existing driver interfaces. This ensures proper reference counting regardless of parent device driver state.

Defensive priority

medium

Recommended defensive actions

  • Update affected Siemens SCALANCE and RUGGEDCOM devices to version 3.1 or later as specified in vendor advisory
  • Review FPGA programming workflows in affected industrial control systems for potential stability risks prior to patching
  • Apply defense-in-depth strategies for industrial control systems per CISA guidance
  • Monitor vendor security advisories for additional affected products or updated remediation guidance

Evidence notes

The vulnerability description indicates a null pointer dereference risk in the Linux kernel's FPGA region subsystem when parent devices lack registered drivers. The fix involves architectural changes to module reference counting through explicit owner pointers. Siemens ProductCERT advisory SSA-613116 provides affected product information and remediation guidance. CISA published advisory ICSA-25-226-15 on 2025-08-12 with subsequent updates through 2026-02-25.

Official resources

2025-08-12