CVE-2026-64038 hwmon: (lm90) Stop work before releasing hwmon device

What is CVE-2026-64038?

CVE-2026-64038 is a medium-severity use after free vulnerability in Linux kernel, published on 19 Jul 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:

hwmon: (lm90) Stop work before releasing hwmon device

Sashiko reports:

In lm90_probe(), the devm action to cancel the alert_work and report_work (lm90_restore_conf) is registered in lm90_init_client() before devm_hwmon_device_register_with_info() is called.

Because devm executes cleanup actions in reverse order during module unbind or probe failure, the hwmon device is unregistered and freed first.

If lm90_alert_work() or lm90_report_alarms() runs in the window between the hwmon device being freed and the delayed works being cancelled, lm90_update_alarms() will dereference the freed data->hwmon_dev here.

Fix the problem by canceling the workers separately after registering the hwmon device and before registering the interrupt handler. This ensures that the workers are canceled after interrupts are disabled and before the hwmon device is released. Add "shutdown" flag to indicate that device shutdown is in progress to prevent workers from being re-armed.

Weakness: CWE-362

Which versions are affected by CVE-2026-64038?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-64038?

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-2026-64038 being exploited?

There is no known exploitation of CVE-2026-64038 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

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

Also known as AZL-92718, BELL-CVE-2026-64038, DEBIAN-CVE-2026-64038, GHSA-35qx-2fp8-64h3, ROOT-OS-DEBIAN-12-CVE-2026-64038, UBUNTU-CVE-2026-64038.