CVE-2025-40223: Linux

EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: most: usb: Fix use-after-free in hdm_disconnect hdm_disconnect() calls most_deregister_interface(), which eventually unregisters the MOST interface device with device_unregister(iface->dev). If that drops the last reference, the device core may call release_mdev() immediately while hdm_disconnect() is still executing. The old code also freed several mdev-owned allocations in hdm_disconnect() and then performed additional put_device() calls. Depending on refcount order, this could lead to use-after-free or double-free when release_mdev() ran (or when unregister paths also performed puts). Fix by moving the frees of mdev-owned allocations into release_mdev(), so they happen exactly once when the device is truly released, and by dropping the extra put_device() calls in hdm_disconnect() that are redundant after device_unregister() and most_deregister_interface(). This addresses the KASAN slab-use-after-free reported by syzbot in hdm_disconnect(). See report and stack traces in the bug link below.

Affected products

• Linux Linux: from 5.9, before 5.10.246 (fixed in 5.10.246); from 5.11, before 5.15.196 (fixed in 5.15.196); from 5.16, before 6.1.158 (fixed in 6.1.158); from 6.2, before 6.6.115 (fixed in 6.6.115); from 6.7, before 6.12.56 (fixed in 6.12.56); from 6.13, before 6.17.6 (fixed in 6.17.6)

Published 2025-12-04. Last modified 2026-06-17.