CVE-2025-37900 is a vulnerability identified in the Linux kernel's Input-Output Memory Management Unit (IOMMU) subsystem, specifically within the functions iommu_copy_struct_from_user() and iommu_copy_struct_to_user(). These functions are responsible for copying data structures between user space and kernel space, a critical operation that must be handled securely to prevent memory corruption or unauthorized access. The vulnerability arises from improper handling of NULL pointers prior to dereferencing, as well as a typographical error in the code, which could lead to unexpected behavior or kernel crashes. The issue was identified during a code review, with Matt highlighting the need to reject NULL pointers before dereferencing, and Alok pointing out a typo that was replicated from the related function. The fix involves correcting these issues in the current kernel header files to prevent potential exploitation. Although no known exploits are currently in the wild, the vulnerability affects the Linux kernel, which is widely used in servers, desktops, and embedded systems globally. The lack of a CVSS score indicates that the vulnerability is newly disclosed and has not yet been fully assessed for severity or impact. However, given that it involves kernel-level memory operations, exploitation could potentially lead to privilege escalation, denial of service, or information disclosure if an attacker can supply crafted input to these functions.

For European organizations, the impact of CVE-2025-37900 could be significant due to the widespread use of Linux in enterprise servers, cloud infrastructure, and critical systems. Exploitation of this vulnerability could allow attackers to cause system instability or crashes (denial of service), or potentially escalate privileges to gain unauthorized access to sensitive data or system controls. This is particularly concerning for sectors such as finance, telecommunications, government, and critical infrastructure, where Linux-based systems are prevalent. Additionally, organizations relying on Linux for container orchestration, virtualization, or edge computing could face operational disruptions. Although no active exploits are reported, the vulnerability's presence in kernel code that handles user-to-kernel data copying means that any untrusted user or process with access to vulnerable kernel interfaces could attempt exploitation. This elevates the risk in multi-tenant environments such as cloud service providers and shared hosting platforms common in Europe.

To mitigate CVE-2025-37900, European organizations should prioritize updating their Linux kernel to the latest patched versions as soon as they become available from their distribution vendors. Since the vulnerability involves kernel-level code, applying vendor-provided security patches is the most effective measure. Organizations should also audit and restrict access to systems where untrusted users or processes could invoke vulnerable kernel interfaces, minimizing the attack surface. Employing kernel hardening techniques such as SELinux, AppArmor, or seccomp can help contain potential exploitation attempts. Monitoring system logs for unusual kernel errors or crashes related to IOMMU operations can provide early detection of exploitation attempts. For environments using custom or embedded Linux kernels, developers should review and integrate the patch fixes for iommu_copy_struct_from_user() and iommu_copy_struct_to_user() functions. Finally, organizations should maintain up-to-date incident response plans to quickly address any exploitation scenarios.