A double free vulnerability in the Linux kernel Renesas R-Car Gen2 PHY driver could allow a local attacker to compromise system integrity and availability.

The flaw exists in the Renesas R-Car Gen2 PHY driver, where the use of for_each_child_of_node_scoped results in an automatic release of node references. An explicit and redundant call to of_node_put in the error path triggers a double release, which can be triggered by an unauthenticated local attacker.

Successful exploitation of this vulnerability allows a local attacker to cause kernel memory corruption, potentially leading to a system crash or privilege escalation. While the CVSS score of 7.4 reflects a high severity, the requirement for local access and specific hardware configurations limits the immediate risk to external-facing assets. Nonetheless, the potential for kernel-level impact warrants immediate attention to ensure system stability and security.

Immediate Action: Update the Linux kernel to version 7.2.6 or later, where the redundant reference count decrement has been removed.

Proactive Monitoring: Monitor system logs for kernel panics or unexpected hardware initialization errors that may indicate exploitation attempts against the PHY driver.

Compensating Controls: Restrict local system access to authorized personnel only and implement kernel hardening features, such as disabling unnecessary modules, to reduce the attack surface.

Public Exploit Available: Unknown

Given the potential for kernel-level instability, organizations utilizing hardware platforms that rely on the Renesas R-Car Gen2 PHY driver should prioritize the deployment of the kernel update. Testing the patch in a staging environment is advised to ensure compatibility before applying the update to production systems.