CVE-2026-98859

What the bug is

mt_remove() quiesces the sticky-finger timer before stopping the hardware: timer_delete_sync(&td->release_timer); sysfs_remove_group(&hdev->dev.kobj, &mt_attribute_group); hid_hw_stop(hdev); timer_delete_sync() waits for a running callback and dequeues the timer, but it does not stop the timer from being armed again. The transport is still delivering reports at that point, and the report path rearms it: if (app->quirks & MT_QUIRK_STICKY_FINGERS) { if (td->mt_io_flags & MT_IO_SLOTS_MASK) mod_timer(&td->release_timer, jiffies + msecs_to_jiffies(100)); A report that arrives after timer_delete_sync() has returned therefore leaves the timer queued. td is allocated with devm_kzalloc() against hdev->dev, so it is freed when the driver is unbound, after mt_remove() returns. When the timer fires afterwards, mt_expired_timeout() dereferences the freed td: struct mt_device *td = timer_container_of(td, t, release_timer); struct hid_device *hdev = td->hdev; if (test_and_set_bit_lock(MT_IO_FLAGS_RUNNING, &td->mt_io_flags)) Simply moving the teardown after hid_hw_stop() does not fix this on its own, because mt_expired_timeout() calls mt_release_contacts(), which walks hdev->inputs; the timer still has to be quiesced before hid_hw_stop() tears the input devices down. Use timer_shutdown_sync() instead, which additionally makes any later mod_timer() a no-op, so neither ordering constraint has to be traded off against the other. This is the final-teardown pattern the function was introduced for, and hid-wiimote already uses it for the same reason.

Where it lives

The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.

drivers/hid/hid-multitouch.c

What this is

HID CORE LAYERMAINTAINERS section matched on drivers/hid/ · linux-input@vger.kernel.org · Maintained

Kernel module

hid_multitouch

Check it on the machine

grep -wE 'CONFIG_HID|CONFIG_HID_MULTITOUCH|CONFIG_HID_SUPPORT' /boot/config-$(uname -r)

Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.

lsmod | grep -w hid_multitouch

Prints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.

Show whether Debian builds this, per release

Debian builds this, but not on every flavour. At least one release below builds the code on some of its kernel flavours and not on others, so the answer depends on the architecture and flavour installed.

• bookworm, trixieMnot built on arm64/cloud-arm64
• forky, sidMnot built on amd64/cloud-amd64, arm64/cloud-arm64

M

a module where it is built at all; some flavours do not build it

Build switches

CONFIG_HID, CONFIG_HID_MULTITOUCH, CONFIG_HID_SUPPORT

Reads as

all on means the file is compiled; any one off means it is not.

From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages

Signals

Published

2026-10-18 (today)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

not scored

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

drivers/hid

Upstream fixes

The versions the CNA records as introducing and fixing this, and the commit for each. source

Introduced	Fixed in	Commit
4.13	6.12.113	1f1bd9a3117f
4.13	6.18.56	0c19a6c1d25f
4.13	7.2.10	a0125ca86e40
4.13	7.3	5acb2dace582