CVE-2021-47022 is a vulnerability identified in the Linux kernel specifically related to the mt76 wireless driver, which supports MediaTek Wi-Fi chipsets, including the mt7615 device. The issue arises from improper memory management during the unregistration process of the mt7615 device. Specifically, the function mt7615_tx_token_put() should be called before mt76_free_pending_txwi() to correctly release allocated resources and avoid memory leaks. Failure to do so results in a memory leak when mt7615_unregister_device() is invoked. While the vulnerability is primarily a memory leak rather than a direct code execution or privilege escalation flaw, it can lead to resource exhaustion over time, potentially degrading system stability or causing denial of service (DoS) conditions. The vulnerability does not require user interaction or authentication to be triggered but depends on the presence and use of the affected wireless driver. There are no known exploits in the wild at the time of publication, and no CVSS score has been assigned. The fix involves correcting the order of function calls to ensure proper cleanup of transmission tokens before freeing pending transmission work items.

For European organizations, the impact of CVE-2021-47022 is primarily related to system stability and availability. Organizations relying on Linux systems with MediaTek mt7615 wireless chipsets, especially in environments with high wireless traffic or frequent device unregistration events (such as dynamic network configurations or embedded systems), may experience gradual memory leaks leading to resource exhaustion. This can cause degraded network performance, system slowdowns, or crashes, impacting critical infrastructure, enterprise networks, or industrial control systems. Although the vulnerability does not directly compromise confidentiality or integrity, the resulting denial of service could disrupt business operations, particularly in sectors dependent on reliable wireless connectivity. Given the widespread use of Linux in servers, IoT devices, and networking equipment across Europe, the vulnerability could affect a broad range of systems if the affected driver is in use. However, the lack of known exploits and the technical nature of the flaw reduce the immediate risk of targeted attacks.

European organizations should prioritize updating their Linux kernel to the latest patched versions that address CVE-2021-47022. Specifically, kernel versions incorporating the fix that ensures mt7615_tx_token_put() is called before mt76_free_pending_txwi() should be deployed. System administrators should audit their environments to identify devices using the mt7615 wireless chipset and verify the kernel versions in use. For embedded or specialized systems where kernel updates may be challenging, consider isolating or disabling the affected wireless interfaces if feasible. Monitoring system logs and resource usage for signs of memory leaks or abnormal behavior related to wireless device unregistration can provide early detection. Additionally, organizations should maintain robust patch management processes to promptly apply Linux kernel updates. Network segmentation and limiting exposure of affected devices to untrusted networks can further reduce risk. Finally, engaging with Linux distribution vendors and hardware manufacturers to confirm the availability and deployment of patches is recommended.