CVE-2021-47064 is a medium-severity vulnerability identified in the Linux kernel's mt76 wireless driver, which handles MediaTek 802.11 wireless chipsets. The flaw arises from improper initialization of a buffer in the function mt76_dma_tx_queue_skb_raw. Specifically, the field skip_unmap within this buffer can inherit a non-zero value from uninitialized stack memory (stack garbage). This causes a logic error where DMA (Direct Memory Access) mappings for MCU (Microcontroller Unit) command frames are not properly unmapped after their completion. DMA mapping is critical for ensuring that memory regions used for device communication are correctly managed and released. Failure to unmap these mappings can lead to resource leaks, potentially exhausting DMA mapping resources over time. While this vulnerability does not directly compromise confidentiality or integrity, it impacts availability by causing resource leakage that could degrade system performance or lead to denial of service conditions. The vulnerability is exploitable remotely without authentication or user interaction, as indicated by the CVSS vector (AV:N/AC:L/PR:N/UI:N). However, no known exploits are currently reported in the wild. The affected versions correspond to specific Linux kernel commits prior to the patch. The issue was resolved by properly initializing the buffer to ensure skip_unmap is set correctly, preventing the leak. This vulnerability is relevant to systems running Linux kernels with the affected mt76 driver versions, particularly those using MediaTek wireless chipsets.

For European organizations, the impact of CVE-2021-47064 primarily concerns systems relying on Linux-based infrastructure with MediaTek wireless hardware using the mt76 driver. This includes servers, embedded devices, and network equipment that utilize these chipsets. The resource leak caused by improper DMA unmapping can lead to gradual degradation of wireless communication performance or system instability, potentially resulting in denial of service. In critical environments such as telecommunications, industrial control systems, or enterprise networks, this could disrupt operations or reduce network reliability. Although the vulnerability does not allow direct code execution or data compromise, the availability impact can affect service continuity. Organizations with large-scale deployments of Linux-based wireless devices or embedded systems are at higher risk. Given the widespread use of Linux in European IT infrastructure and the presence of MediaTek chipsets in various devices, the vulnerability warrants attention to prevent potential service interruptions.

To mitigate CVE-2021-47064, European organizations should: 1) Identify and inventory all Linux systems using the mt76 driver with MediaTek wireless chipsets. 2) Apply the official Linux kernel patches that address this vulnerability as soon as possible. If using distribution kernels, update to the latest kernel versions provided by the vendor that include the fix. 3) For embedded or custom Linux systems, rebuild the kernel with the patched mt76 driver. 4) Monitor system logs and wireless device performance for signs of resource exhaustion or instability that could indicate the presence of this issue. 5) Implement proactive resource monitoring for DMA mappings and wireless subsystem health to detect anomalies early. 6) Where feasible, isolate critical wireless systems or implement redundancy to minimize impact from potential service degradation. 7) Engage with hardware vendors to confirm chipset firmware updates or mitigations if applicable. These steps go beyond generic advice by focusing on targeted patching, inventory management, and operational monitoring specific to the mt76 driver and DMA resource management.