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PatchSiren cyber security CVE debrief

CVE-2024-38627 Siemens CVE debrief

A double-free vulnerability exists in the Linux kernel's System Trace Module (STM) class subsystem. The flaw occurs in `stm_register_device()` where `put_device(&stm->dev)` triggers `stm_device_release()`, which already frees the `stm` structure. A subsequent `vfree(stm)` call results in a double-free condition. This vulnerability affects Siemens industrial networking products running SINEC OS, specifically the RUGGEDCOM RST2428P and SCALANCE X-family switches. Siemens has addressed this issue in SINEC OS V3.1 and later versions. The vulnerability was initially published on August 12, 2025, with subsequent advisory updates through February 25, 2026, including corrections to affected product listings and removal of rejected CVEs.

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 industrial networking equipment including RUGGEDCOM RST2428P switches and SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family devices. System administrators maintaining Linux systems with STM class subsystem enabled. Industrial control system operators following CISA guidance for critical infrastructure protection.

Technical summary

The vulnerability is a classic double-free bug in the Linux kernel's System Trace Module (STM) class implementation. In `stm_register_device()`, when device registration fails, `put_device(&stm->dev)` is called, which decrements the reference count and triggers `stm_device_release()`. This release callback performs `kfree(stm)`, freeing the memory. However, the error handling path then executes `vfree(stm)`, attempting to free the same memory again. This use-after-free scenario can lead to memory corruption, potential kernel crashes, or exploitable conditions depending on heap state. The fix removes the redundant `vfree(stm)` call, relying solely on the device release mechanism for cleanup.

Defensive priority

medium

Recommended defensive actions

  • Update affected Siemens SINEC OS devices to version 3.1 or later
  • Review and apply vendor security advisories for SCALANCE and RUGGEDCOM product families
  • Implement network segmentation for industrial control systems per CISA recommended practices
  • Monitor for kernel updates from Linux distribution maintainers for non-Siemens systems using STM class subsystem

Evidence notes

The vulnerability description is derived from the Linux kernel commit message resolving the double-free in stm_register_device(). Siemens ProductCERT advisory SSA-613116 and CISA advisory ICSA-25-226-15 confirm affected products and remediation. The CVSS vector AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:N indicates network attack vector with high complexity, no confidentiality or integrity impact, and no availability impact, resulting in a NONE severity score.

Official resources

2025-08-12