CVE-2025-40098: 
Linux Kernel vulnerability analysis and mitigation

A vulnerability in the Linux kernel was identified and assigned CVE-2025-40098, specifically affecting the ALSA HDA cs35l41 driver. The issue was discovered by the Linux Verification Center using their SVACE tool and was disclosed on October 30, 2025. The vulnerability involves a NULL pointer dereference in the cs35l41_get_acpi_mute_state() function (NVD).

The vulnerability stems from improper handling of the return value from acpi_evaluate_dsm() function in the ALSA HDA cs35l41 driver. The function's return value is dereferenced without proper NULL checking, although such checking is typically implemented for this function. The issue occurs when acpi_evaluate_object() returns an acpi_status other than ACPI_SUCCESS, causing acpi_evaluate_dsm() to return NULL, which leads to a potential crash (Debian Tracker).

When exploited, this vulnerability can cause a system crash due to the NULL pointer dereference in the audio subsystem, specifically when handling ACPI mute states for the cs35l41 audio codec (NVD).

The vulnerability has been fixed in various Linux distributions. Debian has addressed the issue in version 6.17.7-2 for sid, while some versions remain vulnerable. Ubuntu has marked this as a medium priority issue and is working on updates for affected versions (Ubuntu Security).