CVE-2021-4453 is a vulnerability identified in the Linux kernel, specifically within the Direct Rendering Manager (DRM) subsystem for AMD GPUs. The issue arises in the power management (pm) code for AMD's Renoir platform, where a memory leak occurs due to improper handling of the gpu_metrics_table. During initialization, memory is allocated for gpu_metrics_table in the function renoir_init_smc_tables(), but this allocated memory is not properly freed in the corresponding cleanup function smu_v12_0_fini_smc_tables(). This results in a memory leak, which, while not directly exploitable for code execution or privilege escalation, can lead to resource exhaustion over time. The leak could degrade system performance or stability, particularly on systems with AMD Renoir GPUs running affected Linux kernel versions. Since this vulnerability involves kernel-level code managing GPU power metrics, it affects systems that use the Linux kernel with AMD Renoir GPU support. No known exploits are reported in the wild, and no CVSS score has been assigned. The vulnerability was published in early 2025 and has been addressed by ensuring the allocated memory is properly freed during cleanup, preventing the leak.

For European organizations, the impact of CVE-2021-4453 is primarily related to system stability and resource management rather than direct security compromise. Organizations running Linux servers or workstations with AMD Renoir GPUs could experience degraded performance or increased memory consumption over time, potentially leading to system slowdowns or crashes if the leak accumulates. This could affect critical infrastructure relying on Linux systems for compute or graphical workloads, including research institutions, media companies, and enterprises using AMD hardware. While the vulnerability does not enable privilege escalation or data breaches, the resulting instability could disrupt operations or cause downtime, impacting availability. In environments with high GPU utilization or long uptimes, such as data centers or cloud providers, the memory leak could be more pronounced. However, the absence of known exploits and the limited scope to AMD Renoir GPU users reduce the overall risk. European organizations should consider the vulnerability in their patch management and system maintenance processes to maintain operational reliability.

To mitigate CVE-2021-4453, European organizations should: 1) Apply the latest Linux kernel updates that include the patch fixing the gpu_metrics_table memory leak. This is the most effective and direct mitigation. 2) Monitor system memory usage on Linux hosts with AMD Renoir GPUs to detect abnormal increases that could indicate the leak's impact. 3) Implement routine system reboots or GPU driver reloads as a temporary workaround to clear leaked memory if immediate patching is not feasible. 4) For critical systems, consider isolating or limiting workloads on affected GPUs until patched to reduce the risk of resource exhaustion. 5) Maintain an inventory of hardware and kernel versions to identify systems at risk and prioritize patch deployment. 6) Engage with Linux distribution vendors or AMD for any additional advisories or backported patches relevant to specific enterprise distributions. These steps go beyond generic advice by focusing on hardware-specific monitoring and operational controls tailored to the vulnerability's nature.