CVE-2025-71079: Linux Kernel
Medium severity, CVSS 5.5. EPSS: 0.1% chance of exploitation in the next 30 days.
In the Linux kernel, the following vulnerability has been resolved: net: nfc: fix deadlock between nfc_unregister_device and rfkill_fop_write A deadlock can occur between nfc_unregister_device() and rfkill_fop_write() due to lock ordering inversion between device_lock and rfkill_global_mutex. The problematic lock order is: Thread A (rfkill_fop_write): rfkill_fop_write() mutex_lock(&rfkill_global_mutex) rfkill_set_block() nfc_rfkill_set_block() nfc_dev_down() device_lock(&dev->dev) <- waits for device_lock Thread B (nfc_unregister_device): nfc_unregister_device() device_lock(&dev->dev) rfkill_unregister() mutex_lock(&rfkill_global_mutex) <- waits for rfkill_global_mutex This creates a classic ABBA deadlock scenario. Fix this by moving rfkill_unregister() and rfkill_destroy() outside the device_lock critical section. Store the rfkill pointer in a local variable before releasing the lock, then call rfkill_unregister() after releasing device_lock. This change is safe because rfkill_fop_write() holds rfkill_global_mutex while calling the rfkill callbacks, and rfkill_unregister() also acquires rfkill_global_mutex before cleanup. Therefore, rfkill_unregister() will wait for any ongoing callback to complete before proceeding, and device_del() is only called after rfkill_unregister() returns, preventing any use-after-free. The similar lock ordering in nfc_register_device() (device_lock -> rfkill_global_mutex via rfkill_register) is safe because during registration the device is not yet in rfkill_list, so no concurrent rfkill operations can occur on this device.
Affected products
- Linux Linux Kernel: from 4.4.293, before 4.5 (fixed in 4.5); from 4.9.291, before 4.10 (fixed in 4.10); from 4.14.256, before 4.15 (fixed in 4.15); from 4.19.218, before 4.20 (fixed in 4.20); from 5.4.162, before 5.5 (fixed in 5.5); from 5.10.82, before 5.10.248 (fixed in 5.10.248); …
Published 2026-01-13. Last modified 2026-07-14.