The vulnerability in the Linux kernel involves improper validation of IOAPIC entries in the ACPI MADT and _MAT tables. The IOAPIC hotplug lookup previously advanced through MADT subtables using only the declared length of a generic header without verifying the full record length, and similarly passed generic headers to the IOAPIC helper in the _MAT path. The fix enforces validation that each record has a complete generic header, that the declared length fits within the available record range, and that typed IOAPIC records contain the full fixed IOAPIC body before field access. This validation is applied consistently for both MADT and _MAT paths.

The vulnerability has a CVSS 3.1 score of 7.3 (high severity) with local attack vector, low attack complexity, no privileges required, no user interaction, unchanged scope, and impacts confidentiality, integrity, and availability (C:L/I:L/A:H). This indicates that a local attacker could exploit the flaw to cause significant disruption or partial compromise of system integrity and confidentiality. However, no known exploits in the wild have been reported.

The vulnerability has been resolved in the Linux kernel. Since no explicit patch links or affected versions are provided, it is recommended to update to the latest Linux kernel version where this fix is included. Patch status is not yet confirmed in the provided data — check the official Linux kernel advisories for the exact fixed versions and remediation guidance.