In the Linux kernel, the following vulnerability has been resolved: ACPI: processor: Update cpuidle driver check in __acpi_processor_start() Commit 7a8c994cbb2d ("ACPI: processor: idle: Optimize ACPI idle driver registration") moved the ACPI idle driver registration to acpi_processor_driver_init() and acpi_processor_power_init() does not register an idle driver any more. Accordingly, the cpuidle driver check in __acpi_processor_start() needs to be updated to avoid calling acpi_processor_power_init() without a cpuidle driver, in which case the registration of the cpuidle device in that function would lead to a NULL pointer dereference in __cpuidle_register_device().

A flaw was found in the Linux kernel's Advanced Configuration and Power Interface (ACPI) cpuidle driver. Due to an update in the `__acpi_processor_start()` function, a NULL pointer dereference can occur if `acpi_processor_power_init()` is called without a cpuidle driver. This vulnerability could allow a local attacker to trigger a system crash, leading to a denial of service (DoS).

Red Hat Enterprise Linux 10 Not affected kernel Red Hat Enterprise Linux 6 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel-rt Red Hat Enterprise Linux 8 Not affected kernel Red Hat Enterprise Linux 8 Not affected kernel-rt Red Hat Enterprise Linux 9 Not affected kernel Red Hat Enterprise Linux 9 Not affected kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-43122 https://nvd.nist.gov/vuln/detail/CVE-2026-43122 https://lore.kernel.org/linux-cve-announce/2026050618-CVE-2026-43122-6d5d@gregkh/T