CVE-2025-71073: Input: lkkbd - disable pending work before freeing device

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-01-13 · updated 2026-10-21
Weakness: CWE-416

Description

In the Linux kernel, the following vulnerability has been resolved: Input: lkkbd - disable pending work before freeing device lkkbd_interrupt() schedules lk->tq via schedule_work(), and the work handler lkkbd_reinit() dereferences the lkkbd structure and its serio/input_dev fields. lkkbd_disconnect() and error paths in lkkbd_connect() free the lkkbd structure without preventing the reinit work from being queued again until serio_close() returns. This can allow the work handler to run after the structure has been freed, leading to a potential use-after-free. Use disable_work_sync() instead of cancel_work_sync() to ensure the reinit work cannot be re-queued, and call it both in lkkbd_disconnect() and in lkkbd_connect() error paths after serio_open().

Affected products

Linux kernel: from 2.6.12.1 before 6.12.64; from 6.13 before 6.18.3; 2.6.12, 2.6.12-rc2, 2.6.12-rc3, 2.6.12-rc4, 2.6.12-rc5, 6.19-rc1 (+7) — fixed in 6.12.64, 6.18.3

How to fix

Upgrade to a fixed version: Linux kernel 6.12.64, 6.18.3. Check the vendor advisory for mitigations.

References

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