CVE-2026-23186

CVE-2026-23186 is a medium-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-667.

Key facts

Description

In the Linux kernel, the following vulnerability has been resolved: hwmon: (acpi_power_meter) Fix deadlocks related to acpi_power_meter_notify() The acpi_power_meter driver's .notify() callback function, acpi_power_meter_notify(), calls hwmon_device_unregister() under a lock that is also acquired by callbacks in sysfs attributes of the device being unregistered which is prone to deadlocks between sysfs access and device removal. Address this by moving the hwmon device removal in acpi_power_meter_notify() outside the lock in question, but notice that doing it alone is not sufficient because two concurrent METER_NOTIFY_CONFIG notifications may be attempting to remove the same device at the same time. To prevent that from happening, add a new lock serializing the execution of the switch () statement in acpi_power_meter_notify(). For simplicity, it is a static mutex which should not be a problem from the performance perspective. The new lock also allows the hwmon_device_register_with_info() in acpi_power_meter_notify() to be called outside the inner lock because it prevents the other notifications handled by that function from manipulating the "resource" object while the hwmon device based on it is being registered. The sending of ACPI netlink messages from acpi_power_meter_notify() is serialized by the new lock too which generally helps to ensure that the order of handling firmware notifications is the same as the order of sending netlink messages related to them. In addition, notice that hwmon_device_register_with_info() may fail in which case resource->hwmon_dev will become an error pointer, so add checks to avoid attempting to unregister the hwmon device pointer to by it in that case to acpi_power_meter_notify() and acpi_power_meter_remove().

Frequently asked questions

What is CVE-2026-23186?
In the Linux kernel, the following vulnerability has been resolved: hwmon: (acpi_power_meter) Fix deadlocks related to acpi_power_meter_notify() The acpi_power_meter driver's .notify() callback function, acpi_power_meter_notify(), calls hwmon_device_unregister() under a lock that is also acquired by callbacks in sysfs attributes of the device being unregistered which is prone to deadlocks between sysfs access and device removal. Address this by moving the hwmon device removal in acpi_power_meter_notify() outside the lock in question, but notice that doing it alone is not sufficient because two concurrent METER_NOTIFY_CONFIG notifications may be attempting to remove the same device at the same time. To prevent that from happening, add a new lock serializing the execution of the switch () statement in acpi_power_meter_notify(). For simplicity, it is a static mutex which should not be a problem from the performance perspective. The new lock also allows the hwmon_device_register_with_info() in acpi_power_meter_notify() to be called outside the inner lock because it prevents the other notifications handled by that function from manipulating the "resource" object while the hwmon device based on it is being registered. The sending of ACPI netlink messages from acpi_power_meter_notify() is serialized by the new lock too which generally helps to ensure that the order of handling firmware notifications is the same as the order of sending netlink messages related to them. In addition, notice that hwmon_device_register_with_info() may fail in which case resource->hwmon_dev will become an error pointer, so add checks to avoid attempting to unregister the hwmon device pointer to by it in that case to acpi_power_meter_notify() and acpi_power_meter_remove().
How severe is CVE-2026-23186?
CVE-2026-23186 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-23186 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (1st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-23186?
CVE-2026-23186 primarily affects Linux Linux Kernel. In total, 9 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-23186?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-23186 have an EU (EUVD) identifier?
Yes. CVE-2026-23186 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-5856.
When was CVE-2026-23186 published?
CVE-2026-23186 was published on 2026-02-14 and last updated on 2026-06-17.

References

Affected products (9)

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