ACPI Vulnerability in Linux Kernel Affects Performance Control Feature

CVE-2026-64512

What is CVE-2026-64512?

An out-of-bounds access vulnerability exists in the Linux kernel's ACPI subsystem, specifically impacting the performance control feature. The reg->access_width field is misused based on the type of reg->space_id, particularly with the ACPI_ADR_SPACE_PLATFORM_COMM. This can trigger a UBSAN (Undefined Behavior Sanitizer) warning when the access_width exceeds the expected limit, resulting in a potential risk during computation involving shift operations. The vulnerability manifests in specific configurations of the kernel, stressing the importance of validating both region type and access_width value to prevent out-of-bounds shifts that jeopardize system stability and security.

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