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PatchSiren cyber security CVE debrief

CVE-2024-56531 Linux CVE debrief

CVE-2024-56531 describes a vulnerability in the ALSA caiaq driver where `snd_card_free()` is used during USB device disconnection. This function waits for all open file descriptors to close, which can cause extended delays and potentially block upper-layer USB ioctls, leading to a soft lockup condition. The vulnerability was published on 2025-08-12 and last modified on 2026-02-25. Siemens has identified this CVE as affecting certain industrial networking products that incorporate the vulnerable third-party Linux kernel component, specifically the RUGGEDCOM RST2428P and select SCALANCE product families. However, the CISA advisory marks the impact assessment as 'Misinformed,' indicating potential discrepancies in the original vulnerability reporting or applicability. No CVSS score or severity rating is currently assigned. Organizations should consult Siemens ProductCERT advisory SSA-355557 for authoritative product-specific guidance and patch availability.

Vendor
Linux
Product
RUGGEDCOM RST2428P (6GK6242-6PA00)
CVSS
Unknown
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 or SCALANCE industrial Ethernet switches in critical infrastructure environments, OT security teams managing third-party component risk in industrial devices, and Linux kernel maintainers addressing USB audio driver robustness.

Technical summary

The ALSA caiaq driver uses `snd_card_free()` during USB device disconnection, which synchronously waits for all open file descriptors to close. This blocking behavior can delay disconnection handling sufficiently to block upper-layer USB ioctl operations, potentially triggering a kernel soft lockup. The vulnerability exists in the Linux kernel sound subsystem and affects embedded industrial products that include this driver.

Defensive priority

medium

Recommended defensive actions

  • Review Siemens ProductCERT advisory SSA-355557 for product-specific impact assessment and remediation guidance
  • Verify whether deployed Siemens RUGGEDCOM RST2428P or SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family devices incorporate the vulnerable ALSA caiaq driver component
  • Monitor CISA ICS advisories for updates to the 'Misinformed' impact classification
  • Apply vendor-provided firmware updates when available per organizational change management procedures
  • Implement network segmentation for industrial control systems to limit exposure of affected devices
  • Follow CISA recommended practices for ICS defense in depth

Evidence notes

CVE description sourced from CISA CSAF advisory ICSA-25-226-07. Vendor attribution to Siemens confirmed via CSAF product tree with high confidence. Impact assessment marked 'Misinformed' per CISA advisory threats section. CVE dates per official CVE record: published 2025-08-12, modified 2026-02-25.

Official resources

2025-08-12