The vulnerability lies in the Linux kernel’s iommu/amd early ACPI HID parser. The parser stores HID and UID values in a statically allocated four‑slot array but does not enforce this limit when a fifth entry is encountered. An attacker able to provide a malformed ACPI HID table can cause the kernel to write past the end of the array, corrupting adjacent kernel memory. This is a classic buffer overflow (CWE‑787) that could lead to privilege escalation or arbitrary code execution if the attacker can trigger the overflow.

All Linux kernels that compile the iommu/amd early ACPI HID parser are affected. The advisory does not list specific kernel versions, so any distribution that includes the vulnerable parser should be considered at risk. The patch that bounds the early ACPI HID map is present in the commits cited in the advisory.

The CVSS base score is 4.4, indicating low severity. The EPSS score of <1% means that exploitable attacks are unlikely to be seen in the wild at present. The vulnerability is not in the CISA KEV catalog. An attacker would need to supply a malicious ACPI HID table, which typically requires modification of firmware or boot media—an action usually limited to local or privileged attackers. If such an attacker succeeds, memory corruption could allow elevation of privileges or execution of arbitrary code. The overall risk remains low to moderate given the constrained attack surface and low exploitation probability.