Linux Kernel up to 6.18.33/7.0.10 Lm90 drivers/hwmon/lm90.c lm90_probe hwmon_dev use after free

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.18.33/7.0.10. It has been classified as very critical. Impacted is the function lm90_probe of the file drivers/hwmon/lm90.c of the component Lm90. The manipulation of the argument hwmon_dev leads to use after free. This vulnerability is documented as CVE-2026-64038. The attack needs to be performed locally. There is not any exploit available.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.18.33/7.0.10. It has been rated as very critical. This issue affects the function lm90_probe of the file drivers/hwmon/lm90.c of the component Lm90. The manipulation of the argument hwmon_dev with an unknown input leads to a use after free vulnerability. Using CWE to declare the problem leads to CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at git.kernel.org. The identification of this vulnerability is CVE-2026-64038 since 07/19/2026. The exploitation is known to be easy. Attacking locally is a requirement. The exploitation needs additional levels of successful authentication. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 07/19/2026).

Upgrading to version 6.18.34 or 7.0.11 eliminates this vulnerability.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9
• 6.18.10
• 6.18.11
• 6.18.12
• 6.18.13
• 6.18.14
• 6.18.15
• 6.18.16
• 6.18.17
• 6.18.18
• 6.18.19
• 6.18.20
• 6.18.21
• 6.18.22
• 6.18.23
• 6.18.24
• 6.18.25
• 6.18.26
• 6.18.27
• 6.18.28
• 6.18.29
• 6.18.30
• 6.18.31
• 6.18.32
• 6.18.33
• 7.0.0
• 7.0.1
• 7.0.2
• 7.0.3
• 7.0.4
• 7.0.5
• 7.0.6
• 7.0.7
• 7.0.8
• 7.0.9
• 7.0.10

License

• open-source

Website

• Vendor: https://www.kernel.org/

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