CVE-2021-47423 is a vulnerability identified in the Linux kernel's Direct Rendering Manager (DRM) subsystem, specifically within the nouveau driver component that handles NVIDIA graphics hardware. The issue arises from improper resource management in the debugfs interface of the nouveau driver. When the kernel code uses the single_open() function to open a debugfs file, it must correspondingly call single_release() to free the allocated resources. Failure to do so results in a memory leak, as the 'op' structure allocated by single_open() remains unreleased. This leak occurs during file release operations in the debugfs interface, which is typically used for debugging and diagnostic purposes. Although the vulnerability does not directly lead to code execution or privilege escalation, the memory leak can degrade system stability and performance over time, especially on systems with frequent debugfs interactions or under heavy load. The vulnerability affects Linux kernel versions containing the specified commit hash 6e9fc177399f08446293fec7607913fdbc95e191 and was publicly disclosed on May 21, 2024. No known exploits in the wild have been reported, and no CVSS score has been assigned. The patch involves ensuring that single_release() is properly called to free the allocated memory, thereby preventing the leak.

For European organizations, the impact of CVE-2021-47423 is primarily related to system reliability and resource management rather than direct security compromise. Organizations running Linux servers or workstations with the nouveau driver enabled—common in environments using open-source NVIDIA drivers—may experience gradual memory consumption increases leading to potential system slowdowns or crashes if the debugfs interface is heavily utilized. This can affect data centers, research institutions, and enterprises relying on Linux for critical workloads, especially those using graphical processing units (GPUs) for compute tasks. While the vulnerability does not expose sensitive data or allow unauthorized access, degraded system performance can indirectly impact availability and operational continuity. European sectors with high reliance on Linux-based infrastructure, such as telecommunications, finance, and scientific research, should be aware of this issue. However, the absence of known exploits and the nature of the vulnerability suggest a lower immediate threat level compared to more severe kernel vulnerabilities.

To mitigate CVE-2021-47423, European organizations should prioritize updating their Linux kernel to the latest patched version that includes the fix for the nouveau debugfs memory leak. System administrators should: 1) Monitor kernel updates from trusted Linux distributions and apply patches promptly. 2) Audit systems to identify usage of the nouveau driver and debugfs interfaces, especially in environments where debugfs is enabled and actively used. 3) Consider disabling debugfs in production environments where it is not required, as this reduces the attack surface and potential for resource leaks. 4) Implement resource monitoring tools to detect abnormal memory usage patterns that could indicate leaks. 5) For environments using custom or embedded Linux kernels, ensure that kernel maintainers backport the fix or apply the patch manually. These steps go beyond generic advice by focusing on driver-specific and debugfs-related configurations and monitoring.