CVE-2024-56611 is a vulnerability identified in the Linux kernel's memory management subsystem, specifically within the migrate_to_node() function in mm/mempolicy.c. The root cause stems from an incorrect assumption in the kernel code that a memory management structure (MM) always contains at least one virtual memory area (VMA). This assumption is flawed because there are legitimate cases where an MM may have zero VMAs. When migrate_to_node() calls find_vma() under this assumption, find_vma() can return NULL. The kernel code then dereferences this NULL pointer, leading to a general protection fault and a kernel crash. This is evidenced by the kernel oops message and stack trace provided, showing a null pointer dereference triggered during page migration operations. The vulnerability affects Linux kernel versions prior to the fix applied in version 6.12.0-rc7 and potentially other versions sharing the same code path. The issue is a classic null pointer dereference in kernel space, which can cause denial of service (system crash) but does not appear to allow privilege escalation or arbitrary code execution directly. The flaw is triggered when migrating pages between NUMA nodes, a function typically used in performance tuning or memory management scenarios. The patch involves adding proper checks to handle the case where find_vma() returns NULL, preventing the kernel from dereferencing a null pointer. No known exploits are reported in the wild at this time, and the vulnerability requires kernel-level code execution or privileged access to trigger, as migrating pages is a privileged operation. There is no CVSS score assigned yet for this vulnerability.

For European organizations, the primary impact of CVE-2024-56611 is the risk of denial of service due to kernel crashes on Linux systems. This can affect servers, cloud infrastructure, and embedded devices running vulnerable Linux kernels. Organizations relying on NUMA architectures or performing memory page migrations for performance optimization are more likely to encounter this issue. The vulnerability could disrupt critical services, leading to downtime and potential data loss if systems are not properly protected or if crash recovery mechanisms are inadequate. Since Linux is widely used across European enterprises, cloud providers, and public sector infrastructure, the impact could be significant in environments with high availability requirements. However, the lack of remote exploitability and the need for privileged access limit the risk of widespread exploitation by external attackers. The vulnerability is more likely to be exploited accidentally or triggered by misconfigured or buggy software rather than targeted attacks. Nonetheless, any unexpected kernel crash in production environments can cause operational disruptions and increased incident response costs.

To mitigate CVE-2024-56611, European organizations should: 1) Apply the official Linux kernel patches as soon as they become available, particularly upgrading to kernel version 6.12.0-rc7 or later where the fix is included. 2) For environments where immediate patching is not feasible, consider disabling or limiting the use of migrate_pages system calls or NUMA page migration features if they are not essential. 3) Monitor kernel logs for signs of null pointer dereference oops messages related to migrate_to_node or mempolicy components to detect potential triggering of this vulnerability. 4) Implement robust kernel crash recovery and automated reboot mechanisms to minimize downtime in case of crashes. 5) Restrict privileged access to trusted administrators and processes to reduce the risk of intentional or accidental triggering of the vulnerability. 6) Conduct thorough testing of kernel upgrades in staging environments to ensure compatibility and stability before deployment. 7) Maintain up-to-date inventory of Linux kernel versions in use across the organization to prioritize patching efforts effectively.