CVE-2026-64365: Linux kernel · HID: letsketch: fix UAF on inrange_timer at driver unbind
Affects Linux kernelSource CVE Database V5
Not known to be exploited · fixed in df3d8aa1a9392da3de66398e7a03422463806b21 : update Linux kernel when convenient.
Data as of 6 Nov 2026, 17:04 UTC
Rated by Threat Radar · No CVSS score from NVD or the CNA
Thin evidence
One scorer or none- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Limited control over the software or limited information exposure
CISA SSVC assessment, 2026-11-06.
- Patch
- Available – fixed in df3d8aa1a9392da3de66398e7a03422463806b21, 523db788c0f84612707638e266e8957ca7e3a756, 46c8beeccd8ab2c863827254a85ea877654a3534 +3
Exploitation evidence
Disclosed: evidence found.
CVE published 25 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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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.
References
- git.kernel.org/stable/c/2bb6e7143cf70ed281822d26c1848b2897ac36e9 (opens in a new tab)
- git.kernel.org/stable/c/523db788c0f84612707638e266e8957ca7e3a756 (opens in a new tab)
- git.kernel.org/stable/c/17f5928d7010bc9e002930326b59e60e40c09ee3 (opens in a new tab)
- git.kernel.org/stable/c/3eca1a8165b5e7996e699e9df76cb4645e184d42 (opens in a new tab)
- git.kernel.org/stable/c/df3d8aa1a9392da3de66398e7a03422463806b21 (opens in a new tab)
- git.kernel.org/stable/c/46c8beeccd8ab2c863827254a85ea877654a3534 (opens in a new tab)