In the Linux kernel, the following vulnerability has been resolved:
HID: letsketch: fix UAF on inrange_timer at driver unbind
letsketch_driver does not provide a .remove callback, but
letsketch_probe() arms a per-device timer:
timer_setup(&data->inrange_timer, letsketch_inrange_timeout, 0);
The timer is re-armed from letsketch_raw_event() with a 100 ms
timeout on every pen-in-range report, and its callback dereferences
data->input_tablet to deliver a synthetic BTN_TOOL_PEN release.
letsketch_data is allocated with devm_kzalloc(), and its input_dev
fields are devm-allocated via letsketch_setup_input_tablet(). On
device unbind (USB unplug or rmmod), the HID core runs its default
teardown and devm cleanup frees both letsketch_data and the input
devices. Because no .remove callback exists, nothing drains the
timer first: if raw_event armed it within ~100 ms of the unbind,
the pending timer fires on freed memory. This is a UAF read of
data and of data->input_tablet, followed by input_report_key() /
input_sync() into the freed input_dev.
The same problem can occur on the probe error path: if
hid_hw_start() enabled I/O on an always-poll-quirk device and then
failed, raw_event may have armed the timer before devm releases
data.
Fix by adding a .remove callback that calls hid_hw_stop() first.
hid_hw_stop() synchronously kills the URBs that deliver raw_event(),
so once it returns no path can re-arm the timer. timer_shutdown_sync()
then drains any in-flight callback and permanently disables further
mod_timer() calls. Apply the same timer_shutdown_sync() in the probe
error path so the timer is guaranteed not to outlive data.
HID: letsketch: fix UAF on inrange_timer at driver unbind
letsketch_driver does not provide a .remove callback, but
letsketch_probe() arms a per-device timer:
timer_setup(&data->inrange_timer, letsketch_inrange_timeout, 0);
The timer is re-armed from letsketch_raw_event() with a 100 ms
timeout on every pen-in-range report, and its callback dereferences
data->input_tablet to deliver a synthetic BTN_TOOL_PEN release.
letsketch_data is allocated with devm_kzalloc(), and its input_dev
fields are devm-allocated via letsketch_setup_input_tablet(). On
device unbind (USB unplug or rmmod), the HID core runs its default
teardown and devm cleanup frees both letsketch_data and the input
devices. Because no .remove callback exists, nothing drains the
timer first: if raw_event armed it within ~100 ms of the unbind,
the pending timer fires on freed memory. This is a UAF read of
data and of data->input_tablet, followed by input_report_key() /
input_sync() into the freed input_dev.
The same problem can occur on the probe error path: if
hid_hw_start() enabled I/O on an always-poll-quirk device and then
failed, raw_event may have armed the timer before devm releases
data.
Fix by adding a .remove callback that calls hid_hw_stop() first.
hid_hw_stop() synchronously kills the URBs that deliver raw_event(),
so once it returns no path can re-arm the timer. timer_shutdown_sync()
then drains any in-flight callback and permanently disables further
mod_timer() calls. Apply the same timer_shutdown_sync() in the probe
error path so the timer is guaranteed not to outlive data.
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 |
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Fixes
Solution
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Workaround
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References
History
Sat, 25 Jul 2026 09:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: HID: letsketch: fix UAF on inrange_timer at driver unbind letsketch_driver does not provide a .remove callback, but letsketch_probe() arms a per-device timer: timer_setup(&data->inrange_timer, letsketch_inrange_timeout, 0); The timer is re-armed from letsketch_raw_event() with a 100 ms timeout on every pen-in-range report, and its callback dereferences data->input_tablet to deliver a synthetic BTN_TOOL_PEN release. letsketch_data is allocated with devm_kzalloc(), and its input_dev fields are devm-allocated via letsketch_setup_input_tablet(). On device unbind (USB unplug or rmmod), the HID core runs its default teardown and devm cleanup frees both letsketch_data and the input devices. Because no .remove callback exists, nothing drains the timer first: if raw_event armed it within ~100 ms of the unbind, the pending timer fires on freed memory. This is a UAF read of data and of data->input_tablet, followed by input_report_key() / input_sync() into the freed input_dev. The same problem can occur on the probe error path: if hid_hw_start() enabled I/O on an always-poll-quirk device and then failed, raw_event may have armed the timer before devm releases data. Fix by adding a .remove callback that calls hid_hw_stop() first. hid_hw_stop() synchronously kills the URBs that deliver raw_event(), so once it returns no path can re-arm the timer. timer_shutdown_sync() then drains any in-flight callback and permanently disables further mod_timer() calls. Apply the same timer_shutdown_sync() in the probe error path so the timer is guaranteed not to outlive data. | |
| Title | HID: letsketch: fix UAF on inrange_timer at driver unbind | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-07-25T08:50:20.039Z
Reserved: 2026-07-19T15:36:31.783Z
Link: CVE-2026-64365
Vulnrichment
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NVD
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Redhat
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OpenCVE Enrichment
No data.
Weaknesses
No weakness.