CVE-2025-38391: 
Linux Kernel vulnerability analysis and mitigation

A vulnerability in the Linux kernel's DisplayPort Alt Mode driver for USB Type-C was discovered and disclosed on July 25, 2025. The vulnerability (CVE-2025-38391) affects the pin assignment handling in the USB Type-C DisplayPort alternate mode functionality. This issue was identified in the Linux kernel's USB subsystem, specifically in the DisplayPort Alt Mode implementation (NVD).

The vulnerability occurs when a DisplayPort Alt Mode port partner indicates pin assignment capabilities greater than the maximum allowed value (DPPINASSIGNF). This causes the pinassignment_show function to perform an out-of-bounds array access, resulting in a BRK exception. The issue has been assigned a CVSS v3.1 base score of 5.2 (AV:P/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H) and is classified as CWE-125 (Out-of-bounds Read) (Red Hat).

The vulnerability can lead to denial-of-service conditions through kernel crashes (BRK exceptions) and potential minor information disclosure through out-of-bounds reads when triggered by a malicious or misbehaving USB-C device (Red Hat).

The fix involves adding a DPPINASSIGNMAX value in typecdp.h and modifying the loop condition in pinassignmentshow to use 'i < DPPINASSIGNMAX', preventing access to invalid values in pinassignments. Red Hat notes that alternative mitigation options are either not available or do not meet their Product Security criteria for ease of use, deployment, and stability (Red Hat).