A high severity use after free vulnerability in the Linux kernel amba-pl011 serial driver allows a local attacker with low privileges to potentially achieve code execution or cause system instability.

This vulnerability involves an improper sequence in the serial amba-pl011 driver where RS485 hrtimers are not correctly canceled before the underlying port memory is deallocated. An attacker with local access and low privileges can potentially exploit this race condition to trigger a use after free scenario.

The exploitation of this flaw could allow an authenticated local user to escalate privileges, compromise data integrity, or cause a kernel panic resulting in denial of service. While the vulnerability requires local access, the CVSS score of 7.8 reflects the high potential for full system compromise if the attacker successfully gains unauthorized control over the kernel execution flow.

Immediate Action: Apply the vendor-provided kernel updates by upgrading to Linux Kernel version 6.18.45, 7.1.9, or later versions where the fix is integrated.

Proactive Monitoring: Monitor system logs for unusual kernel oops or segmentation faults that may indicate an attempt to trigger a use after free condition in the serial subsystem.

Compensating Controls: Restrict local shell access to untrusted users and enforce strict privilege management to minimize the attack surface available to potential local threats.

Public Exploit Available: No

This vulnerability presents a significant risk to system stability and security due to the potential for kernel-level exploitation. Administrators should prioritize patching the Linux kernel across all affected environments as soon as the stable updates are verified and deployed within their standard maintenance cycles to eliminate this use after free exposure.