CVE-2025-38394

published 2025-07-25

CVE-2025-38394: In the Linux kernel, the following vulnerability has been resolved: HID: appletb-kbd: fix memory corruption of input_handler_list In appletb_kbd_probe an input…

Priority P3 40 high 7.8 CVSS 3.1

AV L AC L PR L UI N S U C H I H A H

In the Linux kernel, the following vulnerability has been resolved:

HID: appletb-kbd: fix memory corruption of input_handler_list

In appletb_kbd_probe an input handler is initialised and then registered
with input core through input_register_handler(). When this happens input
core will add the input handler (specifically its node) to the global
input_handler_list. The input_handler_list is central to the functionality
of input core and is traversed in various places in input core. An example
of this is when a new input device is plugged in and gets registered with
input core.

The input_handler in probe is allocated as device managed memory. If a
probe failure occurs after input_register_handler() the input_handler
memory is freed, yet it will remain in the input_handler_list. This
effectively means the input_handler_list contains a dangling pointer
to data belonging to a freed input handler.

This causes an issue when any other input device is plugged in - in my
case I had an old PixArt HP USB optical mouse and I decided to
plug it in after a failure occurred after input_register_handler().
This lead to the registration of this input device via
input_register_device which involves traversing over every handler
in the corrupted input_handler_list and calling input_attach_handler(),
giving each handler a chance to bind to newly registered device.

The core of this bug is a UAF which causes memory corruption of
input_handler_list and to fix it we must ensure the input handler is
unregistered from input core, this is done through
input_unregister_handler().

[ 63.191597] ==================================================================
[ 63.192094] BUG: KASAN: slab-use-after-free in input_attach_handler.isra.0+0x1a9/0x1e0
[ 63.192094] Read of size 8 at addr ffff888105ea7c80 by task kworker/0:2/54
[ 63.192094]
[ 63.192094] CPU: 0 UID: 0 PID: 54 Comm: kworker/0:2 Not tainted 6.16.0-rc2-00321-g2aa6621d
[ 63.192094] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),

Affected

6 ranges

Vendor	Product	Version range	Fixed in
debian	linux	—	—
linux	linux	—	—
linux	linux	>= 7d62ba8deacf94f546a0b9dd9bc86617343187a3 < 6ad40b07e15c29712d9a4b8096914ccd82e3fc17	6ad40b07e15c29712d9a4b8096914ccd82e3fc17
linux	linux	>= 7d62ba8deacf94f546a0b9dd9bc86617343187a3 < c80f2b047d5cc42fbd2dff9d1942d4ba7545100f	c80f2b047d5cc42fbd2dff9d1942d4ba7545100f
linux	linux_kernel	—	—
linux	linux_kernel	>= 6.15 < 6.15.6	6.15.6

CVSS provenance

nvd v3.1 7.8 HIGH CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

osv 7.8 HIGH

vendor_debian 7.8 LOW

vendor_redhat 7.8 HIGH

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CWE-787