CVE-2021-47032 is a vulnerability identified in the Linux kernel specifically related to the mt76 wireless driver for the mt7915 chipset. The issue arises from improper handling of Direct Memory Access (DMA) unmapping during transmission (tx) of socket buffers (skb). In particular, the first pointer in the transmission packet (txp) was not being unmapped correctly, 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. Failure to unmap DMA mappings properly can cause resource leaks, potentially leading to system instability or degraded performance over time. Although this vulnerability does not directly indicate a remote code execution or privilege escalation vector, the improper resource management in a kernel driver can be exploited in complex attack scenarios or cause denial of service due to resource exhaustion. The vulnerability was resolved by ensuring that the first pointer in the txp is also unmapped, preventing the leakage of DMA mapping entries. The affected versions are specific commits of the Linux kernel source code, indicating this is a low-level kernel bug fixed in recent updates. There are no known exploits in the wild at the time of publication, and no CVSS score has been assigned yet.

For European organizations, the impact of CVE-2021-47032 primarily concerns systems running Linux kernels with the vulnerable mt76 mt7915 wireless driver, which is common in devices using certain MediaTek Wi-Fi chipsets. The vulnerability could lead to resource leaks in the kernel, potentially causing system instability, degraded network performance, or denial of service conditions on affected devices. This can impact critical infrastructure, enterprise servers, or embedded systems relying on stable wireless connectivity. While no direct remote exploitation has been reported, attackers with local access or the ability to send crafted wireless traffic might trigger the vulnerability to degrade system availability. This is particularly relevant for organizations with large-scale Linux deployments in networking equipment, IoT devices, or wireless access points. The vulnerability does not appear to compromise confidentiality or integrity directly but could be leveraged as part of a multi-stage attack chain. Given the widespread use of Linux in European IT environments, especially in telecommunications, manufacturing, and government sectors, unpatched systems could face operational disruptions.

European organizations should prioritize updating their Linux kernel to the latest patched versions that include the fix for CVE-2021-47032. Specifically, ensure that all systems using the mt76 wireless driver, particularly those with mt7915 chipsets, are upgraded. Network administrators should audit their device inventories to identify affected hardware and verify kernel versions. For embedded or IoT devices where kernel updates are challenging, consider network segmentation and strict access controls to limit exposure. Monitoring system logs for DMA mapping errors or unusual wireless driver behavior can help detect attempts to exploit the vulnerability. Additionally, organizations should implement robust patch management processes to quickly apply kernel updates. Where possible, disable unused wireless interfaces or drivers to reduce the attack surface. Collaboration with hardware vendors to obtain firmware updates that incorporate the patched kernel is also recommended. Finally, maintain up-to-date backups and incident response plans to mitigate potential denial of service impacts.