CVE-2021-46962 is a vulnerability identified in the Linux kernel specifically related to the MMC (MultiMediaCard) subsystem driver for the Uniphier platform, named 'uniphier-sd'. The issue stems from a resource leak caused by the absence of a necessary cleanup call in the driver's remove function. More precisely, the function tmio_mmc_host_free() is not invoked during the remove operation to free resources that were allocated by tmio_mmc_host_alloc() during the probe phase. While the error handling path in the probe function correctly calls tmio_mmc_host_free() to prevent leaks when initialization fails, the remove function neglects this, resulting in a resource leak when the device is removed or the driver is unloaded. This flaw can lead to gradual resource exhaustion, potentially impacting system stability or causing denial of service conditions if the driver is repeatedly loaded and unloaded or if the device is frequently removed and reinserted. The vulnerability does not appear to allow direct code execution or privilege escalation but can degrade system reliability. The issue has been addressed by adding the missing tmio_mmc_host_free() call in the remove function to ensure proper resource deallocation. No known exploits are reported in the wild, and no CVSS score has been assigned yet.

For European organizations, the impact of CVE-2021-46962 is primarily related to system stability and availability rather than confidentiality or integrity. Organizations running Linux systems with the affected uniphier-sd MMC driver—commonly found in embedded devices or specialized hardware using the Uniphier platform—may experience resource leaks leading to degraded performance or system crashes over time. This can affect critical infrastructure or industrial control systems that rely on embedded Linux devices, potentially causing operational disruptions. While the vulnerability does not directly expose sensitive data or allow remote code execution, the resulting denial of service conditions could interrupt business processes, especially in sectors like manufacturing, telecommunications, or transportation where embedded Linux devices are prevalent. The absence of known exploits reduces immediate risk, but unpatched systems remain vulnerable to stability issues. European organizations with embedded Linux deployments should assess their exposure, particularly those using Uniphier-based hardware or custom Linux kernels incorporating this driver.

To mitigate CVE-2021-46962, organizations should: 1) Apply the official Linux kernel patches that include the fix for this resource leak, ensuring the tmio_mmc_host_free() call is present in the remove function of the uniphier-sd driver. 2) For custom or embedded Linux distributions, rebuild and redeploy kernels with the updated driver code. 3) Monitor system logs and resource usage on devices using the uniphier-sd driver to detect abnormal resource consumption or stability issues indicative of the leak. 4) Implement operational procedures to minimize frequent loading/unloading or removal of MMC devices on affected systems until patched. 5) Coordinate with hardware vendors to confirm whether their devices use the affected driver and obtain updated firmware or kernel versions. 6) Incorporate this vulnerability into vulnerability management and patching schedules, prioritizing embedded Linux devices in critical environments.