CVE-2021-47279 is a vulnerability identified in the Linux kernel specifically affecting the usb: misc: brcmstb-usb-pinmap driver component. The issue arises because the code does not properly check the return value of the platform_get_resource() function call. If platform_get_resource() returns NULL, indicating that the requested hardware resource is not available or cannot be retrieved, the driver proceeds without validating this condition, leading to a null pointer dereference (null-ptr-deref). This results in a kernel crash or system instability due to the kernel attempting to access or manipulate memory through a NULL pointer. The vulnerability is rooted in insufficient error handling and input validation within the driver code. The fix involves adding proper checks on the return value of platform_get_resource() to ensure that the pointer is valid before it is dereferenced, thereby preventing the null pointer dereference and associated system crashes. Although this vulnerability does not have any known exploits in the wild at the time of publication, it represents a potential denial-of-service (DoS) vector against affected Linux systems. The affected versions are identified by specific commit hashes, indicating that the vulnerability is present in certain kernel builds prior to the patch. Since the vulnerability is in a kernel driver related to USB hardware resource mapping, it may be triggered by interacting with specific USB devices or configurations that cause platform_get_resource() to return NULL. This vulnerability does not appear to allow privilege escalation or arbitrary code execution directly but can cause system crashes leading to availability issues.

For European organizations, the primary impact of CVE-2021-47279 is the potential for denial-of-service conditions on Linux systems running vulnerable kernel versions. Many European enterprises, government agencies, and critical infrastructure operators rely on Linux-based servers, embedded devices, and network equipment. A null pointer dereference in a kernel USB driver could be triggered by malicious or malformed USB devices or by attackers with local access attempting to disrupt system availability. This could lead to unexpected system reboots, service interruptions, and potential operational downtime. While the vulnerability does not directly compromise confidentiality or integrity, the availability impact can affect business continuity, especially in sectors relying on Linux for critical operations such as telecommunications, manufacturing, and public services. The risk is heightened in environments where physical access to USB ports is possible or where USB devices are frequently connected. Additionally, embedded Linux systems in industrial control systems or IoT devices used across Europe could be affected, potentially impacting operational technology environments. However, since exploitation requires triggering the specific driver code path, remote exploitation is unlikely without local access or physical interaction. The absence of known exploits reduces immediate risk but does not eliminate the threat of future exploitation attempts.

To mitigate CVE-2021-47279, European organizations should prioritize updating their Linux kernels to versions that include the patch fixing the null pointer dereference in the brcmstb-usb-pinmap driver. Kernel updates should be tested and deployed promptly, especially on systems exposed to USB device interactions. Organizations should implement strict physical security controls to limit unauthorized access to USB ports on critical systems, including disabling unused USB ports or using USB port locks. Employing USB device whitelisting or endpoint security solutions that monitor and control USB device connections can reduce the risk of malicious or malformed devices triggering the vulnerability. For embedded or specialized Linux systems, vendors should be contacted to provide patched firmware or kernel updates. System administrators should also monitor system logs for kernel crashes or unusual USB-related errors that could indicate attempted exploitation. In environments where patching is delayed, disabling or unloading the vulnerable driver module (if feasible without impacting essential functionality) can serve as a temporary mitigation. Finally, maintaining comprehensive backup and recovery procedures will help minimize operational impact in case of system crashes caused by this vulnerability.