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.
Analysis and contextual insights are available on OpenCVE Cloud.
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
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| Source | ID | Title |
|---|---|---|
Debian DLA |
DLA-4404-1 | linux security update |
Ubuntu USN |
USN-8029-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8030-1 | Linux kernel (GCP) vulnerabilities |
Ubuntu USN |
USN-8033-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8033-2 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8033-3 | Linux kernel (FIPS) vulnerabilities |
Ubuntu USN |
USN-8034-1 | Linux kernel (NVIDIA Tegra) vulnerabilities |
Ubuntu USN |
USN-8033-4 | Linux kernel (AWS) vulnerabilities |
Ubuntu USN |
USN-8029-2 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8033-5 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8034-2 | Linux kernel (NVIDIA Tegra IGX) vulnerabilities |
Ubuntu USN |
USN-8048-1 | Linux kernel (OEM) vulnerabilities |
Ubuntu USN |
USN-8033-6 | Linux kernel (NVIDIA) vulnerabilities |
Ubuntu USN |
USN-8033-7 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8033-8 | Linux kernel (Intel IoTG) vulnerabilities |
Ubuntu USN |
USN-8029-3 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8095-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8095-2 | Linux kernel (FIPS) vulnerabilities |
Ubuntu USN |
USN-8100-1 | Linux kernel (NVIDIA) vulnerabilities |
Ubuntu USN |
USN-8095-3 | Linux kernel (Real-time) vulnerabilities |
Ubuntu USN |
USN-8095-4 | Linux kernel (AWS) vulnerabilities |
Ubuntu USN |
USN-8125-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8126-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8095-5 | Linux kernel (Raspberry Pi) vulnerabilities |
Ubuntu USN |
USN-8141-1 | Linux kernel (Raspberry Pi) vulnerabilities |
Ubuntu USN |
USN-8163-1 | Linux kernel (Azure FIPS) vulnerabilities |
Ubuntu USN |
USN-8165-1 | Linux kernel (Azure FIPS) vulnerabilities |
Ubuntu USN |
USN-8163-2 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8243-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8261-1 | Linux kernel (Xilinx) vulnerabilities |
Sat, 06 Dec 2025 00:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
| |
| Metrics |
threat_severity
|
cvssV3_1
|
Thu, 04 Dec 2025 15:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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. | |
| Title | most: usb: Fix use-after-free in hdm_disconnect | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-05-11T21:45:10.518Z
Reserved: 2025-04-16T07:20:57.180Z
Link: CVE-2025-40223
No data.
Status : Deferred
Published: 2025-12-04T16:16:14.767
Modified: 2026-04-15T00:35:42.020
Link: CVE-2025-40223
OpenCVE Enrichment
No data.
No weakness.
Debian DLA
Ubuntu USN