CVE-2026-80766 HID: uclogic: fix use-after-free of inrange_timer on remove

What is CVE-2026-80766?

CVE-2026-80766 is an use after free vulnerability in Linux, published on 4 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

In the Linux kernel, the following vulnerability has been resolved:

HID: uclogic: fix use-after-free of inrange_timer on remove

uclogic_remove() cancels the pen in-range timer and then stops the device:

timer_delete_sync(&drvdata->inrange_timer); hid_hw_stop(hdev);

timer_delete_sync() only guarantees the timer is idle at that instant. uclogic_raw_event_pen() keeps delivering pen reports until hid_hw_stop() stops the transport several lines later, and every report with pen->inrange == UCLOGIC_PARAMS_PEN_INRANGE_NONE re-arms the timer:

mod_timer(&drvdata->inrange_timer, jiffies + msecs_to_jiffies(100));

A report landing between the timer_delete_sync() call and the transport teardown in hid_hw_stop() re-arms inrange_timer after it was cancelled. uclogic_remove() then returns and the devm drvdata is freed, while hid_hw_stop() has already freed the input device drvdata->pen_input points at, so when the timer fires ~100 ms later uclogic_inrange_timeout() dereferences freed memory -- a use-after-free in timer-softirq context.

Swapping the two calls is not a fix: stopping the device first frees drvdata->pen_input via hidinput_disconnect() while the timer may still be pending, so a timer already armed before removal fires on the freed input device in the window before timer_delete_sync() runs.

Use timer_shutdown_sync() before hid_hw_stop() instead. It cancels the timer, waits for a running callback while pen_input is still valid, and prevents any further re-arming -- a later mod_timer() from an in-flight report is silently ignored -- so the timer is provably dead before hid_hw_stop() frees the inputs. This is the ordering the timer core documents for this "timer re-armed from another path" teardown case.

Which versions are affected by CVE-2026-80766?

How do I fix CVE-2026-80766?

Apply the vendor's patch.

Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.

Is CVE-2026-80766 being exploited?

There is no known exploitation of CVE-2026-80766 in the wild and no public exploit code.

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as AZL-99513, BELL-CVE-2026-80766, DEBIAN-CVE-2026-80766, GHSA-xc7g-5f4m-53h6, UBUNTU-CVE-2026-80766.