CVE-2024-46707 is a vulnerability identified in the Linux kernel's KVM (Kernel-based Virtual Machine) implementation for the ARM64 architecture, specifically related to the handling of interrupt controller registers in virtualized environments. The issue arises in systems equipped with a GICv3 (Generic Interrupt Controller version 3), where a guest virtual machine (VM) is not configured to use GICv3, and the host system lacks the capability to emulate GICv2. Under these conditions, when the guest attempts to write to any of the ICC_*SGI*_EL1 registers (which are related to software-generated interrupts), the write operation is trapped to the EL2 exception level (hypervisor level). The KVM code attempts to emulate the SGI access; however, due to the absence of a private interrupt allocation (because the guest is not configured with a GIC), this results in a NULL pointer dereference. This can cause a kernel panic or crash of the host system or the hypervisor, leading to a denial of service. The fix implemented involves generating an undefined instruction (UNDEF) exception for the guest when it attempts such an invalid access, preventing the NULL pointer dereference and improving system stability. This vulnerability is specific to ARM64 virtualized environments using KVM with certain GIC configurations and affects Linux kernel versions identified by the given commit hashes. There are no known exploits in the wild at the time of publication, and no CVSS score has been assigned yet.

For European organizations, the impact of CVE-2024-46707 primarily concerns those utilizing ARM64-based virtualization infrastructure with Linux KVM hypervisors, especially in cloud, telecom, and edge computing environments where ARM servers are increasingly deployed. Exploitation of this vulnerability could lead to denial of service conditions by crashing the host kernel or hypervisor, disrupting virtual machine availability and potentially causing downtime for critical services. This could affect service providers, data centers, and enterprises relying on ARM64 virtualization for workloads such as telecommunications (5G infrastructure), IoT platforms, and cloud-native applications. While this vulnerability does not directly lead to privilege escalation or data leakage, the resulting instability could impact business continuity and operational resilience. Given the growing adoption of ARM64 servers in Europe, particularly in countries investing in next-generation telecom infrastructure and cloud services, the threat is relevant but limited to specific deployment scenarios. The absence of known exploits reduces immediate risk, but the potential for denial of service in critical infrastructure warrants attention.

To mitigate CVE-2024-46707, European organizations should: 1) Apply the latest Linux kernel patches that address this vulnerability as soon as they become available from trusted sources or Linux distributions. 2) Review and verify the configuration of KVM guests to ensure that the virtual interrupt controller (vGIC) version matches the host capabilities, avoiding mismatches that trigger the vulnerable code path. 3) Implement strict validation and testing of ARM64 virtualization environments, especially when deploying new guest configurations or upgrading kernel versions. 4) Monitor system logs and hypervisor behavior for signs of crashes or undefined instruction exceptions related to ICC_*SGI*_EL1 register accesses. 5) For critical production environments, consider isolating ARM64 virtualization hosts or limiting guest configurations to known safe settings until patches are applied. 6) Engage with hardware and software vendors to confirm support for GICv2 emulation or proper vGICv3 guest configuration to prevent triggering this vulnerability. These steps go beyond generic advice by focusing on configuration validation and proactive patch management tailored to ARM64 KVM virtualization contexts.