A stack buffer overflow vulnerability in the Linux kernel ACPI PFR update mechanism could allow a local authenticated attacker to achieve code execution or system instability.

The vulnerability exists in the query_capability function within the ACPI pfr_update driver, where firmware-supplied data is copied into fixed-size stack buffers using memcpy without proper length validation. An attacker with local access and low privileges can leverage this flaw to trigger memory corruption if the system firmware returns buffers exceeding 16 bytes.

The vulnerability carries a CVSS score of 7.8, indicating a high severity risk for local environments. Successful exploitation allows an attacker to corrupt the kernel stack, potentially leading to privilege escalation, arbitrary code execution, or a total system crash. This poses a significant threat to the confidentiality, integrity, and availability of affected host systems.

Immediate Action: Apply the vendor-supplied kernel patches by updating to Linux Kernel version 6.12.109, 6.18.50, 7.2.4, or later immediately.

Proactive Monitoring: Monitor system logs for kernel-related panic events or stack-out-of-bounds reports generated by security subsystems such as KASAN.

Compensating Controls: Restrict local access to the system to trusted users and ensure that hardware firmware is sourced from verified and secure vendors to prevent the injection of malicious ACPI data.

Public Exploit Available: Unknown

This vulnerability represents a critical risk to kernel integrity on systems utilizing the pfr_update driver. Administrators should prioritize patching the kernel to the specified versions or newer to eliminate the buffer overflow condition. Given that kernel-level exploits are often used for persistent system compromise, immediate remediation is required to maintain a secure operating environment.