PatchSiren cyber security CVE debrief

CVE-2024-38601 Siemens CVE debrief

A race condition in the Linux kernel's ring buffer implementation can cause tracing to stop unexpectedly when ring buffer resize operations occur concurrently with reader page swaps. The vulnerability exists in the doubly-linked list manipulation during page replacement in rb_get_reader_page(), where temporary inconsistency between page->prev->next and page->next->prev pointers can be detected by rb_check_pages() during parallel ring_buffer_resize() calls. This condition became more likely to trigger following kernel commit d78ab792705c (tracing: Stop current tracer when resizing buffer), which ensures the parent trace_buffer has recording disabled during resize operations. The issue affects Siemens industrial networking products running SINEC OS, including RUGGEDCOM RST2428P and SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family devices.

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 infrastructure including RUGGEDCOM RST2428P switches and SCALANCE XC/XR series devices. OT security teams responsible for maintaining visibility into industrial control system operations through kernel tracing. System administrators managing SINEC OS deployments who rely on ring buffer functionality for diagnostics and monitoring.

Technical summary

The vulnerability stems from non-atomic doubly-linked list updates in the Linux kernel's ring buffer implementation. When rb_get_reader_page() performs cmpxchg on old->list.prev->next to swap in a new reader page, the subsequent update to old->list.next->prev creates a brief window of list inconsistency. Concurrent ring_buffer_resize() calls invoke rb_check_pages(), which validates list integrity and can halt tracing when detecting the temporary inconsistency. The race window is small but was made more exploitable by kernel changes ensuring recording is disabled during resize operations.

Defensive priority

medium

Recommended defensive actions

Apply vendor-provided firmware updates to V3.1 or later for affected Siemens SINEC OS products per Siemens ProductCERT guidance
Review and implement CISA ICS recommended practices for defense-in-depth strategies in industrial control system environments
Monitor for unexpected tracing interruptions on affected systems as potential indicators of race condition triggering
Validate ring buffer resize operations do not occur during active tracing sessions where possible
Consult Siemens support resources for product-specific patch availability and deployment guidance

Evidence notes

The vulnerability description is derived from CISA CSAF advisory ICSA-25-226-15, which references Siemens ProductCERT advisory SSA-613116. The technical details describe a race condition between rb_get_reader_page() and ring_buffer_resize() in kernel/trace/ring_buffer.c. The issue was resolved in the Linux kernel upstream. Siemens has issued vendor fixes for affected SINEC OS versions.

Official resources

2025-08-12