CVE-2025-37748 is a vulnerability identified in the Linux kernel specifically within the Mediatek IOMMU (Input-Output Memory Management Unit) driver code. The issue arises due to a NULL pointer dereference in the function mtk_iommu_device_group. During the probe phase, the driver calls iommu_device_register before the hardware list (hw_list) from the driver data is properly initialized. Since the hw_list is accessed using list_first_entry, which is not NULL-safe, this premature call order leads to dereferencing a NULL pointer. This can cause the kernel to crash or behave unpredictably, resulting in a denial of service (DoS) condition. The fix involves reordering the calls to ensure that iommu_device_register is invoked only after the driver data, including hw_list, is fully initialized. This vulnerability is specific to Linux kernel versions containing the affected Mediatek IOMMU driver code and does not currently have any known exploits in the wild. The vulnerability does not have an assigned CVSS score yet, but the technical details indicate it is a stability and availability risk rather than a direct confidentiality or integrity compromise.

For European organizations, this vulnerability primarily poses a risk of system instability and denial of service on Linux systems running affected Mediatek IOMMU drivers. Systems using Mediatek SoCs with this IOMMU implementation, such as embedded devices, network equipment, or specialized industrial systems, could experience kernel panics or crashes if exploited. This could disrupt critical services, especially in sectors relying on embedded Linux devices like telecommunications, manufacturing automation, or IoT deployments. While this vulnerability does not directly lead to privilege escalation or data breaches, the resulting downtime or service interruptions could impact operational continuity and availability. Organizations with large-scale Linux deployments or those using Mediatek hardware in their infrastructure should be particularly cautious. The absence of known exploits reduces immediate risk, but the vulnerability's presence in kernel code means that attackers with local access could potentially trigger crashes, making it a concern for multi-tenant environments or shared hosting.

To mitigate this vulnerability, European organizations should prioritize updating their Linux kernel to the patched version where the call order in the Mediatek IOMMU driver is corrected. Since the vulnerability is in the kernel driver code, applying vendor-provided kernel updates or patches is the most effective measure. For embedded or specialized devices, coordinate with hardware vendors or device manufacturers to obtain updated firmware or kernel images. Additionally, organizations should restrict local access to affected systems to trusted users only, minimizing the risk of malicious triggering of the NULL pointer dereference. Monitoring system logs for kernel crashes or unusual reboots can help detect exploitation attempts. In environments where immediate patching is not feasible, consider isolating affected devices or limiting their network exposure to reduce attack surface. Finally, maintain an inventory of devices using Mediatek SoCs and assess their exposure to this vulnerability to prioritize remediation efforts.