CVE-2021-47161 is a medium-severity vulnerability identified in the Linux kernel, specifically within the spi-fsl-dspi driver component. The issue arises from a resource leak in the error handling path of the probe function. In detail, the function dspi_request_dma() is responsible for requesting DMA (Direct Memory Access) resources, but if an error occurs during the probe process, the corresponding release function dspi_release_dma() is not called to free those resources. This omission leads to a resource leak, which can degrade system stability or availability over time. The vulnerability does not impact confidentiality or integrity directly, but it affects availability by potentially exhausting DMA resources if the error path is triggered repeatedly. The vulnerability requires local access with low privileges (AV:L/PR:L) and does not require user interaction (UI:N). The scope is unchanged (S:U), meaning the impact is limited to the vulnerable component without affecting other system components. The CVSS score of 5.5 reflects a medium severity level, indicating a moderate risk. No known exploits are currently reported in the wild. The vulnerability was resolved by ensuring that dspi_release_dma() is properly called in the error handling path, mirroring the cleanup performed in the remove function. This fix prevents resource leakage and improves the robustness of the driver during error conditions.

For European organizations, the impact of CVE-2021-47161 is primarily related to system availability and stability, especially for those running Linux-based systems with the affected spi-fsl-dspi driver. This driver is typically used in embedded systems or specialized hardware platforms that utilize Freescale/NXP SPI controllers. Organizations relying on such hardware in industrial control systems, telecommunications infrastructure, or embedded devices could experience degraded performance or system crashes if the vulnerability is triggered repeatedly. While the vulnerability does not allow privilege escalation or data compromise, the resource leak could lead to denial of service conditions, impacting operational continuity. Given the prevalence of Linux in European IT environments, particularly in critical infrastructure and manufacturing sectors, unpatched systems might face increased maintenance overhead and potential downtime. However, the limited scope and requirement for local access reduce the likelihood of widespread exploitation in typical enterprise environments.

To mitigate CVE-2021-47161, European organizations should: 1) Apply the latest Linux kernel updates that include the fix for this vulnerability to ensure proper resource cleanup in the spi-fsl-dspi driver. 2) Audit systems using Freescale/NXP SPI controllers to identify if the vulnerable driver version is in use, particularly in embedded or industrial devices. 3) Implement strict access controls to limit local user privileges, minimizing the risk of triggering the error path maliciously or accidentally. 4) Monitor system logs and resource usage for signs of DMA resource exhaustion or related errors that could indicate attempts to exploit the vulnerability. 5) For critical embedded systems where kernel updates are challenging, consider isolating affected devices from broader networks to reduce risk exposure. 6) Engage with hardware and software vendors to confirm patch availability and deployment timelines for embedded platforms.