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CVE-2025-40223

most: usb: Fix use-after-free in hdm_disconnect PUBLISHED

Description (CNA)

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 (CNA)

Vendor / productVersions
Linux / Linuxaffected 97a6f772f36b7f52bcfa56a581bbd2470cffe23d before 5b5c478f09b1b35e7fe6fc9a1786c9bf6030e831; affected 97a6f772f36b7f52bcfa56a581bbd2470cffe23d before 578eb18cd111addec94c43f61cd4b4429e454809; affected 97a6f772f36b7f52bcfa56a581bbd2470cffe23d before 33daf469f5294b9d07c4fc98216cace9f4f34cc6; affected 97a6f772f36b7f52bcfa56a581bbd2470cffe23d before 72427dc6f87523995f4e6ae35a948bb2992cabce; affected 97a6f772f36b7f52bcfa56a581bbd2470cffe23d before f93a84ffb884d761a9d4e869ba29c238711e81f1; affected 97a6f772f36b7f52bcfa56a581bbd2470cffe23d before 3a3b8e89c7201c5b3b76ac4a4069d1adde1477d6; affected 97a6f772f36b7f52bcfa56a581bbd2470cffe23d before 4b1270902609ef0d935ed2faa2ea6d122bd148f5
Linux / Linuxaffected 5.9; unaffected 0 before 5.9; unaffected 5.10.246 through 5.10.*; unaffected 5.15.196 through 5.15.*; unaffected 6.1.158 through 6.1.*; unaffected 6.6.115 through 6.6.*; unaffected 6.12.56 through 6.12.*; unaffected 6.17.6 through 6.17.*; unaffected 6.18 through *

CWE

No CWE identifiers supplied.

References