CVE-2024-40964 is a vulnerability identified in the Linux kernel's ALSA (Advanced Linux Sound Architecture) subsystem, specifically within the hda (High Definition Audio) driver for the Cirrus Logic CS35L41 audio codec. The vulnerability arises in the cs35l41_hda_unbind() function, which is responsible for unbinding or detaching the audio codec component. The function attempts to clear the hda_component entry by index and then dereferences a codec pointer held in the first element of the hda_component array. However, when the device index is 0, this dereference can lead to a null pointer dereference because the pointer may have been cleared or invalidated. This results in a potential kernel crash or denial of service due to the null pointer dereference. The correct approach, as per the patch, is to use the codec pointer stored in the cs35l41_hda structure itself, which remains valid even when the hda_component array entry is cleared. This vulnerability is a memory safety issue that could cause system instability or crashes if triggered. There are no known exploits in the wild at the time of publication, and no CVSS score has been assigned yet. The vulnerability affects Linux kernel versions containing the affected code commit (7cf5ce66dfda2be444ea668c3d48f732ba4a7fd1).

For European organizations, the primary impact of CVE-2024-40964 is potential system instability or denial of service on Linux systems utilizing the affected ALSA hda driver with the CS35L41 codec. This could affect servers, desktops, or embedded devices running Linux kernels with this driver, especially in environments where audio hardware is present and used. While this vulnerability does not directly lead to privilege escalation or remote code execution, a denial of service in critical systems could disrupt business operations, particularly in sectors relying on Linux-based infrastructure such as telecommunications, industrial control, or media production. Additionally, if exploited in multi-tenant environments like cloud or virtualized infrastructure, it could impact service availability. The lack of known exploits reduces immediate risk, but the vulnerability should be addressed promptly to prevent future exploitation. Confidentiality and integrity impacts are minimal, but availability could be significantly affected if the vulnerability is triggered repeatedly or maliciously.

European organizations should prioritize patching Linux kernels to versions where this vulnerability is fixed, ensuring the cs35l41_hda_unbind() function uses the correct codec pointer. Since this is a kernel-level issue, updating to the latest stable Linux kernel releases or applying vendor-provided security patches is essential. Organizations should audit their hardware inventory to identify devices using the CS35L41 codec and verify if they run vulnerable kernel versions. For systems where immediate patching is not feasible, consider disabling or unloading the ALSA hda driver for the CS35L41 codec if audio functionality is non-critical. Monitoring system logs for kernel oops or crashes related to ALSA or hda components can help detect attempted exploitation or instability. Additionally, implement strict access controls to limit unprivileged user access to audio device interfaces, reducing the risk of local exploitation. Finally, maintain up-to-date backups and have incident response plans ready to address potential denial of service incidents.