Junglewise Threat Intelligence

CVE-2025-71079: Linux Kernel deadlock in NFC device unregistration

CVE-2025-71079 · Severity: medium · CVSS 5.5 · Published 2026-01-13

Technologies: Linux Kernel, Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP. Vendors: Linux, Siemens.

Executive brief

A flaw was discovered in the Linux kernel's Near Field Communication (NFC) subsystem that can cause the system to hang or become unresponsive. This occurs when the system attempts to disable an NFC device while another process is simultaneously managing wireless radio settings. An exploit could lead to a denial-of-service, impacting the availability of systems using NFC technology, such as certain industrial controllers and mobile devices.

Technical details

A deadlock (ABBA scenario) exists in the Linux kernel NFC core between nfc_unregister_device() and rfkill_fop_write(). The vulnerability is caused by a lock ordering inversion where one thread holds rfkill_global_mutex and waits for device_lock, while another thread holds device_lock and waits for rfkill_global_mutex. This issue was introduced by reordering logic in nfc_register_device and nfc_unregister_device. The fix involves moving rfkill_unregister() and rfkill_destroy() calls outside of the device_lock critical section. Local attackers can trigger this to cause a denial-of-service (system hang). Patches have been released for multiple stable kernel branches.

Affected products

  • Linux Linux Kernel versions prior to 6.12.8, 6.6.69, 6.1.123, 5.15.176, 5.10.233, 5.4.289, 4.19.326
  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP V3.1.6

Timeline

  • 2025-12-18: disclosed: Initial patch submission by Deepanshu Kartikey
  • 2026-01-11: patched: Patch committed to stable kernel branches
  • 2026-01-13: advisory: NVD publication date

References

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