CVE-2021-47601 is a vulnerability identified in the Linux kernel specifically related to the 'tee: amdtee' driver component. The issue arises from improper error handling in the kernel function __get_free_pages(). This function is designed to allocate memory pages and returns NULL upon failure rather than an error pointer. However, the affected code incorrectly checks the return value using IS_ERR(), which is intended for error pointer detection, instead of checking for NULL. This logic flaw can lead to a NULL pointer dereference when the function fails to allocate memory but the code mistakenly treats the return value as a valid pointer. A NULL dereference in kernel space can cause a system crash (kernel panic), resulting in a denial of service (DoS) condition. Although this vulnerability does not appear to allow privilege escalation or arbitrary code execution, the stability and availability of affected systems can be compromised. The vulnerability was reserved in May 2024 and published in June 2024, with no known exploits in the wild at the time of reporting. The affected versions are specific Linux kernel commits identified by their hashes, indicating that this issue is present in certain recent kernel builds. The fix involves correcting the error handling logic to properly check for NULL instead of using IS_ERR(), thereby preventing the NULL dereference scenario.

For European organizations, the primary impact of CVE-2021-47601 is the potential for denial of service due to kernel crashes triggered by the NULL pointer dereference. Organizations relying on Linux-based systems, particularly those using the 'amdtee' driver or related Trusted Execution Environment (TEE) components, may experience system instability or downtime if the vulnerability is triggered. This can affect servers, embedded devices, or infrastructure components running vulnerable kernel versions. While the vulnerability does not directly lead to data breaches or privilege escalation, the resulting service interruptions can disrupt business operations, especially in critical sectors such as finance, telecommunications, healthcare, and government services. The absence of known exploits reduces immediate risk, but unpatched systems remain vulnerable to accidental or targeted triggering of the flaw. Given the widespread use of Linux in European IT environments, the vulnerability's impact is significant in terms of availability and operational continuity.

European organizations should apply the following specific mitigation steps: 1) Identify and inventory all Linux systems running kernel versions that include the vulnerable commits, focusing on those using the 'amdtee' driver or TEE-related modules. 2) Update affected Linux kernels to the latest patched versions provided by the Linux kernel maintainers or respective Linux distribution vendors as soon as patches become available. 3) For embedded or specialized devices where kernel updates are not immediately feasible, consider disabling the 'amdtee' driver if it is not essential to operations, to reduce exposure. 4) Implement monitoring for kernel panics or system crashes that could indicate exploitation attempts or accidental triggering of the vulnerability. 5) Engage with hardware and software vendors to confirm patch availability and deployment timelines, especially for devices with integrated TEE components. 6) Incorporate this vulnerability into incident response and vulnerability management workflows to ensure timely detection and remediation.