CVE-2021-47033 is a vulnerability identified in the Linux kernel specifically related to the mt76 wireless driver, which supports MediaTek 7615 wireless chipsets. The issue arises from improper handling of Direct Memory Access (DMA) mappings during the transmission (tx) process. In particular, the vulnerability is due to the failure to unmap the first pointer in the txp structure, which leads to a leak of DMA mapping entries. DMA mapping is critical for efficient data transfer between the system memory and hardware devices without CPU intervention. When DMA mappings are not properly unmapped, it can cause resource leaks that degrade system performance and potentially lead to denial of service (DoS) conditions due to exhaustion of DMA mapping resources. This vulnerability does not appear to allow direct code execution or privilege escalation but can cause system instability or crashes if exploited. The fix involves ensuring that the first pointer in the txp is properly unmapped to prevent the leakage of DMA mapping entries. The vulnerability affects specific versions of the Linux kernel containing the mt76 driver implementation for the mt7615 chipset. There are no known exploits in the wild at the time of publication, and no CVSS score has been assigned yet. The vulnerability was published on February 28, 2024, and is considered a kernel-level issue affecting Linux systems using the affected wireless drivers.

For European organizations, the impact of CVE-2021-47033 primarily concerns systems running Linux kernels with the mt76 driver supporting MediaTek mt7615 wireless chipsets. This includes servers, embedded devices, and potentially network infrastructure equipment that rely on this wireless chipset. The main risk is resource leakage leading to degraded system performance or denial of service, which could disrupt critical services or network connectivity. Organizations with large-scale deployments of Linux-based wireless access points or IoT devices using this chipset could experience operational instability. Although no direct data breach or privilege escalation is indicated, the resulting DoS conditions could impact availability, which is critical for sectors such as telecommunications, manufacturing, and public services. Given the widespread use of Linux in enterprise and industrial environments across Europe, failure to patch this vulnerability could lead to increased maintenance costs and downtime. However, the absence of known active exploits reduces the immediate threat level, but proactive mitigation is advised to prevent future exploitation.

To mitigate CVE-2021-47033, European organizations should: 1) Identify all Linux systems using the mt76 driver with the mt7615 chipset by auditing hardware and kernel module usage. 2) Apply the official Linux kernel patches that fix the tx skb DMA unmap issue as soon as they are released and tested in their environments. 3) For embedded or IoT devices where kernel updates are not straightforward, coordinate with device vendors for firmware updates or consider network segmentation to isolate vulnerable devices. 4) Monitor system logs and kernel messages for signs of DMA mapping resource exhaustion or related errors that could indicate exploitation attempts or instability. 5) Implement robust system resource monitoring to detect abnormal resource usage patterns early. 6) Maintain up-to-date backups and incident response plans to quickly recover from potential DoS incidents. 7) Engage in vulnerability management processes to track and remediate similar kernel-level vulnerabilities promptly.