CVE-2025-71108

A firmware compatibility issue was found in the Linux kernel's USB Type-C UCSI driver. The UCSI specification defines num_connectors as a 7-bit field with the 8th bit reserved. Some buggy firmware incorrectly sets this reserved bit, causing the driver to interpret an invalid connector count. This can prevent the system from booting properly when the UCSI driver is loaded.

This issue was discovered on Lenovo P1 G8 hardware during Linux enablement. It affects systems with non-compliant UCSI firmware that sets the reserved bit in the num_connectors capability field. The kernel fix auto-corrects the value to allow proper system boot. This is primarily a firmware bug that the kernel now works around rather than a security vulnerability.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.