CVE-2021-47409 is a vulnerability identified in the Linux kernel specifically within the USB driver component for the DesignWare Core USB 2.0 (dwc2) controller. The issue arises because the driver fails to properly check the return value of the function platform_get_resource(), which is used to obtain hardware resource information from the platform device. If platform_get_resource() returns NULL, indicating that the requested resource is not available, the driver proceeds without validation, leading to a null pointer dereference (null-ptr-deref) when it attempts to use the returned resource pointer. This results in a kernel crash (kernel panic) or denial of service (DoS) condition. The vulnerability is rooted in improper error handling and lack of defensive programming in the driver code. The fix involves adding a check on the return value of platform_get_resource() to ensure it is not NULL before dereferencing it. This vulnerability affects specific versions of the Linux kernel as identified by the commit hashes provided, and it was published on May 21, 2024. There are no known exploits in the wild at this time, and no CVSS score has been assigned. The vulnerability is classified as a stability and availability issue rather than a direct confidentiality or integrity compromise, as it causes a crash rather than arbitrary code execution or privilege escalation.

For European organizations, the impact of CVE-2021-47409 primarily concerns system availability and operational stability. Linux is widely used across European enterprises, government agencies, and critical infrastructure sectors, especially in servers, embedded systems, and network devices. A null pointer dereference in the USB driver can cause unexpected kernel panics, leading to system reboots or downtime. This can disrupt business operations, particularly in environments relying on USB-connected devices or embedded Linux systems using the dwc2 controller. While it does not directly lead to data breaches or privilege escalation, repeated crashes can degrade service availability and potentially open windows for denial-of-service attacks if exploited in a targeted manner. Systems running vulnerable Linux kernel versions without the patch are at risk, especially those with USB hardware relying on the affected driver. The absence of known exploits reduces immediate risk, but the vulnerability should be addressed promptly to maintain system reliability and prevent potential exploitation attempts.

European organizations should take the following specific mitigation steps: 1) Identify all Linux systems running kernel versions that include the vulnerable dwc2 USB driver code, particularly those using the affected commit hashes or versions. 2) Apply the official Linux kernel patches that add the necessary null check after platform_get_resource() calls in the dwc2 driver. If official patches are not yet available, consider backporting the fix from the mainline kernel source. 3) For embedded or specialized devices, coordinate with hardware vendors or device manufacturers to obtain updated firmware or kernel images incorporating the fix. 4) Implement monitoring for kernel panics or unexpected reboots related to USB device activity to detect potential exploitation attempts or instability. 5) Limit exposure by restricting USB device usage on critical systems where feasible, or enforce strict device control policies. 6) Maintain up-to-date inventories of Linux kernel versions and USB hardware to facilitate rapid response to similar vulnerabilities. 7) Test patches in staging environments to ensure compatibility and stability before deployment in production. These steps go beyond generic advice by focusing on hardware-specific driver updates, vendor coordination, and operational monitoring tailored to the nature of this vulnerability.