Description
In the Linux kernel, the following vulnerability has been resolved:
HID: multitouch: stop the release timer from being rearmed on remove
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.
HID: multitouch: stop the release timer from being rearmed on remove
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.
Published:
2026-10-18
Score:
n/a
EPSS:
n/a
KEV:
No
Analysis
Analysis and contextual insights are available on OpenCVE Cloud.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
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| Linux | Linux | affected |
|
No data.
No data.
No data available yet.
Remediation
No solution or workaround provided in the CVE record.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
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Advisories
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References
History
Sun, 18 Oct 2026 16:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: HID: multitouch: stop the release timer from being rearmed on remove 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. | |
| Title | HID: multitouch: stop the release timer from being rearmed on remove | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-10-18T15:51:20.456Z
Reserved: 2026-09-25T10:25:14.376Z
Link: CVE-2026-98859
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-10-18T16:17:40.363
Modified: 2026-10-18T16:17:40.363
Link: CVE-2026-98859
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.