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CVE-2026-64365

Full vulnerability record from the local CVENow database.

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.

Severity
HIGH
CVSS score
7.8 (v3.1)
Vulnerability status
Analyzed
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-07-25 10:17:19.280000
Last modified
2026-11-06 17:18:52.057000
View original CVE JSON 
{
  "id": "CVE-2026-64365",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-07-25T10:17:19.280",
  "lastModified": "2026-11-06T17:18:52.057",
  "vulnStatus": "Analyzed",
  "cveTags": [],
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    {
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      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nHID: letsketch: fix UAF on inrange_timer at driver unbind\n\nletsketch_driver does not provide a .remove callback, but\nletsketch_probe() arms a per-device timer:\n\n    timer_setup(&data->inrange_timer, letsketch_inrange_timeout, 0);\n\nThe timer is re-armed from letsketch_raw_event() with a 100 ms\ntimeout on every pen-in-range report, and its callback dereferences\ndata->input_tablet to deliver a synthetic BTN_TOOL_PEN release.\n\nletsketch_data is allocated with devm_kzalloc(), and its input_dev\nfields are devm-allocated via letsketch_setup_input_tablet().  On\ndevice unbind (USB unplug or rmmod), the HID core runs its default\nteardown and devm cleanup frees both letsketch_data and the input\ndevices.  Because no .remove callback exists, nothing drains the\ntimer first: if raw_event armed it within ~100 ms of the unbind,\nthe pending timer fires on freed memory.  This is a UAF read of\ndata and of data->input_tablet, followed by input_report_key() /\ninput_sync() into the freed input_dev.\n\nThe same problem can occur on the probe error path: if\nhid_hw_start() enabled I/O on an always-poll-quirk device and then\nfailed, raw_event may have armed the timer before devm releases\ndata.\n\nFix by adding a .remove callback that calls hid_hw_stop() first.\nhid_hw_stop() synchronously kills the URBs that deliver raw_event(),\nso once it returns no path can re-arm the timer.  timer_shutdown_sync()\nthen drains any in-flight callback and permanently disables further\nmod_timer() calls.  Apply the same timer_shutdown_sync() in the probe\nerror path so the timer is guaranteed not to outlive data."
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