CVE-2024-42089 is a vulnerability identified in the Linux kernel specifically within the ASoC (ALSA System on Chip) framework's fsl-asoc-card driver. The issue arises from the improper initialization order of a pointer priv->pdev within the probe function of the driver. The pointer priv->pdev is used in the sub-function fsl_asoc_card_audmux_init() before it is assigned a valid value. This leads to a NULL pointer dereference when the driver attempts to access the dev struct through priv->pdev, particularly when invoking dev_err macros for error logging. Since priv is zero-initialized, dereferencing priv->pdev before assignment results in a NULL pointer dereference, which can cause the driver to crash. However, if no error is triggered (and thus no dev_err call is made), the driver may not crash due to compiler optimizations that avoid dereferencing the pointer unnecessarily. The root cause is a race condition or ordering flaw in the initialization sequence, where the pointer should be assigned at the start of the probe function to ensure all sub-functions have valid access to priv->pdev. This vulnerability is a stability and reliability issue rather than a direct code execution or privilege escalation flaw. It can cause denial of service (DoS) by crashing the affected driver and potentially the kernel if the crash is severe enough. The vulnerability affects specific commits or versions of the Linux kernel identified by the commit hash 708b4351f08c08ea93f773fb9197bdd3f3b08273. No known exploits are reported in the wild, and no CVSS score has been assigned yet. The fix involves moving the assignment of priv->pdev to the start of the probe function to prevent NULL pointer dereference during initialization.

For European organizations, the primary impact of CVE-2024-42089 is related to system stability and availability. Systems running affected Linux kernel versions with the fsl-asoc-card driver enabled may experience kernel crashes or driver failures due to NULL pointer dereferences. This can lead to denial of service conditions, affecting embedded devices, industrial control systems, or servers that rely on this audio subsystem, particularly in environments where uptime and reliability are critical. Although this vulnerability does not directly lead to privilege escalation or data breaches, the resulting crashes could disrupt business operations, especially in sectors such as telecommunications, manufacturing, automotive, or any industry using Linux-based embedded systems with the affected driver. The impact is more pronounced in environments where automated recovery is not in place or where kernel crashes require manual intervention. Since the vulnerability is not known to be exploited in the wild, the immediate risk is moderate, but organizations should prioritize patching to maintain system integrity and prevent potential exploitation or cascading failures in complex systems.

1. Apply the official Linux kernel patch that moves the assignment of priv->pdev to the start of the probe function in the fsl-asoc-card driver. This is the definitive fix to prevent the NULL pointer dereference. 2. For organizations using custom or long-term support kernels, backport the patch to affected kernel versions to ensure protection without full kernel upgrades. 3. Implement robust kernel crash monitoring and automated recovery mechanisms to minimize downtime if a crash occurs. 4. Conduct thorough testing of audio subsystem drivers in staging environments before deploying updates to production, ensuring no regressions or new stability issues arise. 5. Review and audit embedded Linux systems and devices that use the fsl-asoc-card driver to identify affected versions and prioritize remediation. 6. Maintain updated inventories of Linux kernel versions and drivers in use across the organization to quickly assess exposure to such vulnerabilities. 7. Engage with hardware and software vendors to confirm that updated kernel versions or patches are available and integrated into device firmware or distributions.